Radiation-Based Dermatological Devices and Methods

ABSTRACT

A self-contained, hand-held device for providing a dermatological treatment includes a device body configured to be handheld by a user; a radiation source supported in the device body, the radiation source including a beam source configured to generate an energy beam; an application end configured to be manually moved across the surface of the skin during a treatment session; electronics configured to pulse the radiation source during the treatment session such that the beam source emits pulsed energy beams to the skin; and a displacement control system including a displacement sensor configured to determine a displacement of the device relative to the skin, and electronics configured to control at least one operational parameter of the device based on the determined displacement of the device relative to the skin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/439,353 filed on Feb. 3, 2011; U.S. Provisional Application No.61/444,079 filed on Feb. 17, 2011; U.S. Provisional Application No.61/469,316 filed on Mar. 30, 2011; U.S. Provisional Application No.61/533,641 filed on Sep. 12, 2011; U.S. Provisional Application No.61/533,677 filed on Sep. 12, 2011; U.S. Provisional Application No.61/533,786 filed on Sep. 12, 2011; U.S. Provisional Application No.61/545,481 filed on Oct. 10, 2011; U.S. Provisional Application No.61/563,491 filed on Nov. 23, 2011; and U.S. Provisional Application No.61/594,128 filed on Feb. 2, 2012; all of which applications are hereinincorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure is related to radiation-based dermatologicaltreatment devices and methods, e.g., laser-based devices for providingfractional treatment, or devices using any other type of radiationsource for providing any other suitable type of dermatologicaltreatment.

BACKGROUND

Light-based treatment of tissue is used for a variety of applications,such as hair removal, skin rejuvenation, wrinkle treatment, acnetreatment, treatment of vascular lesions (e.g., spider veins, diffuseredness, etc.), treatment of cellulite, treatment of pigmented legions(e.g., age spots, sun spots, moles, etc.), tattoo removal, and variousother treatments. Such treatments generally include delivering light orlaser radiation to an area of tissue on a person's body, e.g., the skinor internal tissue, to treat the tissue in a photochemical,photobiological, thermal, or other manner, which can be ablative ornon-ablative, among other properties, depending on the particularapplication.

Light-based treatment devices include various types of light sources,such as lasers, LEDs, flashlamps, etc. For example, diode lasers areparticularly suitable for certain light-based treatments and devices forproviding such treatments. Diode lasers are compact, as they aretypically built on one chip that contains the major necessary componentsfor light generation other than a power source. Further, diode laserstypically provide an efficiency of up to 50% or higher, which enablesthem to be driven by low electrical power compared to certain otherlasers. Diode lasers allow direct excitation with small electriccurrents, such that conventional transistor based circuits can be usedto power the laser.

Other characteristics typical of diode lasers include high temperaturesensitivity/tunability, and a highly divergent beam compared to certainother lasers. Diode lasers typically emit a beam having anaxis-asymmetric profile in a plane transverse to the optical axis of thelaser. In particular, the emitted beam diverges significantly faster ina first axis (referred to as the “fast axis”) than in an orthogonalsecond axis (referred to as the “slow axis”). In contrast, other typesof lasers, e.g., fiber lasers, typically emit a beam having anaxis-symmetric profile in the transverse plane.

Laser-based treatment devices typically include optics downstream of thelaser source to scan, shape, condition, direct, and/or otherwiseinfluence the laser radiation to the target tissue as desired. Suchoptics may include lenses, mirrors, and other reflective and/ortransmissive elements, for controlling optical parameters of the beam,such as the direction, propagation properties or shape (e.g.,convergent, divergent, collimated), spot size, angular distribution,temporal and spatial coherence, and/or intensity profile of the beam,for example. Some devices include systems for scanning a laser beam inorder to create a pattern of radiated areas (e.g., spots, lines, orother shapes) in the tissue. For some applications, the scanned patternof radiated areas overlap each other, or substantially abut each other,or are continuous, in order to provide complete coverage of a targetarea of tissue. For other applications, e.g., certain wrinkletreatments, vascular treatments, pigmentation treatments,anti-inflammatory treatments, and other skin rejuvenation treatments,the scanned radiated areas may be spaced apart from each other bynon-irradiated areas such that only a fraction of the overall targetarea of the tissue is radiated during a treatment session. Thus, in suchapplications, there are generally regions of untreated tissue betweenregions of treated tissue. This type of treatment is known as“fractional” treatment (or more specifically, fractionalphotothermolysis in some cases) because only a fraction of the targetarea is irradiated during a treatment session.

SUMMARY

The present disclosure is related to radiation-based dermatologicaltreatment devices and methods, e.g., laser-based devices for providingfractional treatment.

In some embodiments, a hand-held compact device is provided forproviding radiation-based dermatological treatments, e.g., skinresurfacing, skin rejuvenation, wrinkle treatment, removal or reductionof pigmentation, hair removal, acne treatment, skin tightening, redness,vascular treatments such as telangectasia or port-wine stains, stretchmarks, anti-aging, or anti-inflammatory skin treatments such as treatingrosacea, acne, or vitiligo. Other embodiments may apply to non-skintissue treatment, such as eye tissue or internal organs. In particularembodiments, the device is a compact-hand-held device for providinglaser-based non-ablative fractional treatment by pulsing one or morelaser beam sources as the device is moved, or “manually scanned,” acrossthe skin, wherein the device omits any optics (e.g., mirrors, poweredlenses, etc.) for influencing the laser beams, and wherein the laserbeam source(s) along with the laser beam(s) emitted by the laser beamsource(s) are attached in a fixed manner (in location and direction) andremain fixed (in location and direction) with respect to the devicehousing during operation of the device.

The device may include one or more radiation sources that radiate energyto the skin in the form of one or more beams to produce one or moreirradiated areas on the skin that provide a dermatological treatment. Asused herein, “radiation” may include any radiative energy, includingelectromagnetic radiation, UV, visible, and IP light, radio frequency,ultrasound, microwave, etc. A radiation source may include any suitabledevice for radiating one or more coherent or incoherent energy beams,e.g., a laser, LED, flashlamp, ultrasound device, RF device, microwaveemitter, etc. Energy beams may be provided in any suitable manner, suchas pulsed, continuous wave (CW), or otherwise, depending on theparticular embodiment, application, or device setting. In someembodiments, the radiation source is a laser, e.g., an edge emittinglaser diode, laser diode bar, HeNe laser, YAG laser, VCSEL laser, orother types of laser, that delivers one or more laser beams to the skinto effect a treatment. It should be understood that references herein toa radiation source or an energy beam in the singular should beinterpreted to mean at least one radiation source or at least one energybeam, unless otherwise specified, e.g., references to a single radiationsource or a single energy beam, or references to radiation sources orenergy beams (or references to multiple radiation sources or multipleenergy beams).

In some embodiments, the device provides pulsed energy beams to the skinto provide a fractional dermatological treatment, e.g., skinresurfacing, skin rejuvenation, wrinkle treatment, removal or reductionof pigmentation, treatment of coarse skin caused by photodamage, etc.Each pulsed energy beam forms an irradiated treatment spot (or“treatment spot”) on the surface of the skin, and a three-dimensionalvolume of thermally damaged (or otherwise influenced, such asphotochemically) skin extending below the surface of the skin, referredto herein as a micro thermal zone (MTZ). Each MTZ may extend from theskin surface downward into the skin, or may begin at some depth belowthe skin surface and extend further downward into the skin, depending onthe embodiment, device settings, or particular application. The devicemay be configured to generate an array of MTZs in the skin that arelaterally spaced apart from each other by volumes of untreated (i.e.,non-irradiated or less irradiated) skin. For example, an application endof the device (also referred to herein as the device “tip”) may bemanually moved (e.g., in a sliding manner) across the surface of theskin during a treatment session. An energy beam or beams may be pulsed(to generate MTZs in the skin) during the movement of the device acrossthe skin (referred to herein as a “gliding mode” treatment), or betweenmovements of the device across the skin (referred to herein as a“stamping mode” treatment), or a combination of these modes or differentmodes. The skin's healing response, promoted by the areas of untreated(i.e., non-irradiated) skin between adjacent MTZs, provides fractionaltreatment benefits in the treatment area (e.g., skin resurfacing orrejuvenation, wrinkle removal or reduction, pigment removal orreduction, etc.). In some embodiments or applications, the compact,hand-held device may yield results similar to professional devices, butleverages a home use model to more gradually deliver the equivalent of asingle professional dose over multiple treatments or days (e.g., a 30day treatment routine or a two treatment sessions per week treatmentroutine). Skin rejuvenation generally includes at least one or more oftreatments for wrinkles, dyschromia, pigmented lesions, actinickerotosis, melasma, skin texture, redness or erythema, skin tightening,skin laxity, and other treatments.

As used herein, “fractional” treatment means treatment in whichindividual treatment spots generated on the skin surface are physicallyseparated from each other by areas of non-irradiated (or lessirradiated) skin (such that the MTZs corresponding to such treatmentspots are generally physically separated from each other). In otherwords, in a fractional treatment, adjacent treatment spots (and thustheir corresponding MTZs) do not touch or overlap each other. In someembodiments in which a radiation source (e.g., laser) is pulsed togenerate a successive series of treatment spots on the skin, the pulserate may be set or selected based on a typical or expected speed atwhich the device is manually moved or “glided” across the skin, referredto herein as the “manual glide speed” (e.g., in a gliding mode operationof the device). In particular, the pulse rate may be set or selectedsuch that for a range of typical or expected manual (ormechanically-driven) glide speeds, adjacent treatment spots aregenerally physically separated from each other by areas of non-treatedskin (i.e., fractional treatment is provided). In some embodiments, thepulse rate may be set or selected such that for a range of typical orexpected manual glide speeds, adjacent treatment spots are physicallyseparated from each other from a predetermined minimum non-zerodistance, e.g., 500 μm. For example, in some embodiment, a pulse rate ofbetween 2 and 30 HZ (e.g., about 15 Hz) may be selected for providing adesired fractional treatment for typical or expected manual glide speedsof between 1 and 6 cm/sec.

In some embodiments, the device may be controlled to prevent, limit, orreduce the incidence or likelihood of treatment spot overlap, e.g.,based on feedback from one or more sensors (e.g., one or more dwellsensors, motion/speed sensors, and/or displacement sensors). Forexample, the device may monitor the speed or displacement of the devicerelative to the skin and control the radiation source accordingly, e.g.,by turning off the radiation source, reducing the pulse rate, etc. upondetecting that the device has not been displaced on the skin a minimumthreshold distance from a prior treatment location. Further, in someembodiments, the pulse rate may be automatically adjustable by thedevice and/or manually adjustable by the user, e.g., to accommodatedifferent manual glide speeds and/or different comfort levels or paintolerance levels of the user.

In some embodiments, the device may be configured to provide 3Dfractional treatment, by generating MTZs at various depths in the skin.For example, this may be achieved by providing a plurality of beamsources configured to generate MTZs at different depths, e.g., by usingmultiple beam sources arranged at different distances from the skinsurface, focal depths, wavelengths, pulse energies, pulse durations, orother parameters. Thus, such embodiments may have a solid-stateconfiguration in which the beam sources and the beams propagated fromthe beam sources remain fixed with respect to the device housing (i.e.,no moving parts regarding the beam delivery). As another example, such3D fractional treatment can be achieved by dynamically moving oradjusting one or more beam sources or output beams, or dynamicallyadjusting the focal points of one or more beams.

In some embodiments, the device includes a displacement-based controlsystem including a displacement sensor and electronics configured tomeasure or estimate the lateral displacement of the device across theskin and control one or more aspect of the device (e.g., on/off statusor pulse rate of the radiation source) based on the determineddisplacement of the device. For example, the displacement-based controlsystem may control the delivery of energy beams to provide a desiredspacing between treatment spots (for a fractional treatment) and/or toprevent or reduce the incidence or likelihood of treatment spot overlap.

In some embodiments, pulsed energy beams are manually scanned across theskin, rather than using an automated scanning system (e.g., includingsystems for moving optical elements and/or the laser or other energysource) present in various existing devices. In some embodiments thedevice does not include any moving optics (or any optics at all, asdiscussed below). In some embodiments, both the radiation source andenergy beam path from the radiation source to the skin are fixed withrespect to the outer housing of the device. Omitting an automatedscanning system from the device may permit a smaller beam output windowor aperture, in particular for embodiment that include only a singlebeam source, as the emitted energy beam remains fixed relative to thedevice housing. For example, certain embodiments may include a beamoutput window or aperture having a maximum width or diameter of lessthan 1 mm (and in particular embodiments, less than 0.5 mm), as a beamemitted by certain laser sources (e.g., an edge emitting laser diode)typically has a very small diameter (e.g., about 120 microns) and may befixed such that the beam remains centered in the exit window/aperture.In comparison, certain automated-scanner-based devices have an outputwindow or aperture of greater than one square centimeter in area.

In some embodiments, the device includes a single radiation source,e.g., an edge emitting laser diode, a VCSEL having a singlemicro-emitter zone, an LED, or a flashlamp. For certain treatments, thesingle radiation source may be pulsed while the device is glided acrossthe skin to form a generally one-dimensional array (or line) oftreatment spots on the skin. A two-dimensional array of treatment spotscan thus be created by gliding the device across the skin multiple timesin any suitable pattern.

In other embodiments, the device includes multiple radiation sources,e.g., multiple edge emitting laser diodes, an laser diode bar havingmultiple emitters (or multiple laser diode bars), a VCSEL havingmultiple micro-emitter zones (or multiple VCSELs), or multiple LEDs. Forcertain treatments, the multiple radiation sources may be pulsed whilethe device is operated in a gliding mode or alternatively in a stampingmode or a combination of modes, to form a two-dimensional array oftreatment spots on the skin on each glide. Such device may be glidedacross the skin multiple times to create a larger, more dense, orotherwise different two-dimensional array.

Further, the device may be configured for “direct exposure” or “indirectexposure” radiation, and/or for “close proximity” or “remote proximity”radiation, depending on the particular embodiment and/or configurationof the device. “Direct exposure” embodiments or configurations do notinclude any optics downstream of the radiation source for affecting ortreating the beam(s) generated by the radiation source(s) (the term“optics” is defined below in this document). Some direct exposuredevices may include a window (e.g., to protect the radiation sourceand/or other internal components of the device) that does notsubstantially affect the beam. A window may be formed from any suitablematerial, e.g., sapphire, quartz, diamond, or other material transparentat the frequency of the radiation source 14 and preferably also having agood thermal coefficient.

Thus, embodiments of the device may create a desired array of MTZswithout using microlenses or other similar optics. Thus, embodiments ofthe device may provide increased optical efficiency, reduced powerrequirements, simpler and less expensive manufacturing, increasedcompactness, and/or enhanced reliability as compared with certainnon-ablative fractional treatment devices that use microlenses or othersimilar optics for creating MTZ arrays. However, it should be understoodthat certain embodiments of the device may include one or more optics,e.g., for desired beam shaping.

The omission of beam-influencing optics in certain embodiments mayresult in an overall higher optical efficiency for the device. In anyoptical system, losses occur due to less than perfect transmission,reflection, or beam “spilling” outside of the diameter of the opticalelement(s) in the beam path. Thus, embodiments of the device that omitbeam-influencing optics may provide increased optical efficiency, andthus allow reduced power to the radiation source(s), as compared withcertain conventional devices.

In contrast, “indirect exposure” embodiments or configurations includeone or more optics downstream of the radiation source(s) for affectingor treating the beam(s) generated by the radiation source(s). Optics mayallow the radiation source(s) to be positioned at any desired distancefrom the application end of the device that contacts the skin duringtreatment (and thus at any desired distance from the target surface) orto affect other radiation properties. Certain embodiments that use alaser diode as the radiation source may include one or more fast axisoptical elements for capturing and focusing the rapidly diverging fastaxis beam profile emitted from the laser diode or a scanner, such as arotating optic or a microlens array, for suitablydelivering/distributing the radiation.

In “close proximity” embodiments or configurations, the emitting surfaceof each radiation source (e.g., the emitting surface of an edge emittinglaser diode) is positioned within 10 mm of the skin-contacting surfaceof the device (i.e., the leading surface of the device tip), such thatthe emitting surface of each radiation source is positioned within 10 mmof the skin surface when the device tip is positioned in contact withthe skin. As discussed below, this distance is referred to herein as the“proximity gap spacing.” In contrast, in “remote proximity” embodimentsor configurations, the proximity gap spacing (between the emittingsurface of the radiation source(s) and the skin-contacting surface ofthe device) is greater than 10 mm. Some close proximity embodiments, dueto the small proximity gap spacing and thus short travel distance of thebeam(s) from the radiation source(s) to the skin, may omitprecision-aligned optics (or all optics) that may be needed in similarremote proximity embodiments, thus providing a direct exposure, closeproximity configuration. Some particular embodiments discussed belowinclude an edge emitting laser diode configured for direct exposure andclose proximity radiation, wherein the emitting surface of the edgeemitting laser diode is positioned within 10 mm of the skin surface,with no optics (e.g., only a window, open space, protective coating, orsimilar feature) between the edge emitting laser diode and the skin.Direct exposure, close proximity embodiments may be particularlycompact. Some direct exposure, close proximity embodiments may provide ahigh optical throughput and may be capable of generating relativelyhigh-power emissions in a compact battery-operated device.

It should be understood that “direct exposure” is not synonymous with“close proximity,” and likewise “indirect exposure” is not synonymouswith “remote proximity.” That is, direct exposure embodiments orconfigurations may be configured for either close proximity or remoteproximity radiation, depending on the particular embodiment orconfiguration. For example, collimated or quasi-collimated light sourcescould be located with remote proximity and be direct exposure in thatthe beam has no optics between the source and the skin. Similarly,indirect exposure embodiments or configurations may be configured foreither close proximity or remote proximity radiation, depending on theparticular embodiment or configuration. For example, some embodimentsmay include a very small lens (e.g., a cylindrical or ball lens)downstream of the light source, but wherein the emitting surface of eachradiation source is still within 10 mm of the skin surface duringtreatment.

In some embodiments, the beam generation and delivery components of thedevice have an all-solid-state construction that excludes any automatedor mechanically moving parts for dynamically moving the beam source anddirection and location of the propagated beam relative to the devicehousing, including (a) any motorized or otherwise moving beam-scanningelements, such as motorized or otherwise moving optical elements to scana beam to multiple different directions or locations relative to thedevice housing (e.g., galvo-controlled mirrors or rotating multi-facetedscanning elements), and (b) any motorized or other elements forphysically moving the beam source and any associated beam deliveryelements (e.g., a laser, LED, fiber, waveguide, etc.). Such embodimentsmay reduces noise, increase the reliability of the device, reducemanufacturing cost and complexity, and/or increase compactness of thefinished device with low or minimal component count.

In some embodiments, the device has an all-solid-state construction withno automated moving parts at all, including no any automated ormechanically moving parts for dynamically moving the beam source anddirection and location of the propagated beam relative to the devicehousing (as discussed above), as well as any fans, other motors, orother automated moving parts.

Certain example embodiments are handheld, battery powered, compact skintreatment devices with all solid-state components, configured to providedirect exposure, close-proximity radiation, and for providing skin areacoverage via manual scanning of the device across the surface of theskin, in a gliding or stamping mode operation, and using a CW or pulsedradiation source (or multiple CW or pulsed radiation sources).

In some embodiments, the device is fully or substantially self-containedin a compact, hand-held housing. For example, in some battery-poweredembodiments of the device, the radiation source(s), user interface(s),control electronics, sensor(s), battery or batteries, fan(s) or othercooling system (if any), and/or any optics (if any), are all containedin a compact, hand-held housing. Similarly, in some wall-outlet-poweredembodiments of the device, the radiation source(s), user interface(s),control electronics, sensor(s), battery or batteries, fan(s) or othercooling system (if any), and/or any optics (if any), are all containedin a compact, hand-held housing, with only the power cord extending fromthe device.

In other embodiments, one or more main components of the device may beseparate from the device housing, and connected by any suitable physicalor wireless means (e.g., wire, cable, fiber, wireless communicationslink, etc.)

In some embodiments, the device provides eye safe radiation, e.g., bydelivering a substantially divergent energy beam (e.g., using an edgeemitting laser diode with no downstream optics), and/or using an eyesafety control system including one or more sensors, and/or by any othersuitable manner. In some laser-based embodiments or settings, the devicemeets the Class 1M or better (such as Class 1) eye safety classificationper the IEC 60825-1. In other laser-based embodiments or settings, thedevice falls outside the IEC 60825-1 Class 1M eye safety classificationby less than 25% of the difference to the next classification threshold.In still other laser-based embodiments or settings, the device fallsoutside the IEC 60825-1 Class 1M eye safety classification by less than50% of the difference to the next classification threshold. In somelamp-based embodiments, the device meets the “Exempt” or “Low Risk” eyesafety classification per the IEC 62471.

In some embodiments, the device uses one or more VCSEL (Vertical CavitySurface Emitting Laser) lasers as the radiation source(s). A VCSEL maybe configured to generate a single energy beam or multiple discreteenergy beams. For the latter, the VCSEL may include non-active regionsthat define an array of micro-emitter zones separated from each other bynon-active (or less active or masked) regions, with each micro-emitterzone generating a beam, such that a single VCSEL may generate an array(e.g., a 1D or 2D array) of laser beams. In some embodiments, the arrayof laser beams is delivered to the skin to provide an array ofspaced-apart treatment spots on the skin, and thus an array ofspaced-apart MTZs, e.g., to provide a fractional treatment via a manualgliding mode or stamping mode operation of the device. In someembodiments, the beam generated from each micro-emitter zone issubstantially axially-symmetric (e.g., as opposed to the beam generatedby an edge emitting laser diode). In some embodiments, a two-dimensionalmulti-zone pulsed VCSEL may be configured in direct exposure, closeproximity (in effect, placed directly or nearly directly against theskin) to affect a fractional treatment when glided or stamped across theskin. Likewise, a one-dimensional, multi-zone pulsed VCSEL can beconfigured in direct exposure, close proximity to affect a fractionaltreatment when glided or stamped across the skin.

In some embodiments, the device is eye safe, hand held, manufacturablewithout excessive labor costs, requires low power consumption, andeffective. In some embodiments, the device eliminates the need foroptical scanners, microlenses, or other complex optical and mechanicaldevices, for creating multiple MTZs in the skin. In particularembodiments, the device is battery powered, with a single, fixedlocation, repetitively-pulsed edge emitting laser diode for creating anarray of MTZs in the skin by manually scanning the device across theskin while the edge emitting laser diode is repetitively pulsed, witheach pulse creating a single MTZ in the skin. In other embodiments,multiple beam sources (e.g., multiple edge emitting laser diodes,certain laser diode bars, certain VCSEL configurations) multiple can beused to create multiple MTZs in the skin for each pulse of the multiplebeam sources.

In some embodiments, the device may be suitable for providing afractional treatment using a home-use treatment plan that includestreatment sessions of a few minutes or less, once or twice a day. Insome embodiments, a treatment session of two minutes, for example, mayallow an effective treatment of about 20-30 cm² (about 4 in²). Further,certain embodiments permits the use a small battery, and allow forthermal control without any fan(s). For example, in some embodiments, asmall cylindrical block of copper can absorb the waste heat from a laserduring a treatment session, preventing excessive temperature rise of thediode without the use of a fan. Other embodiments may include at leastone fan for increased cooling of the device components.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the disclosure may be understood by referring, inpart, to the following description and the accompanying drawingswherein:

FIG. 1 illustrates components of an example radiation-based treatmentdevice, according to certain embodiments.

FIG. 2 illustrates an example control system for a radiation-basedtreatment device, according to example embodiments.

FIG. 3 illustrates a schematic layout of various components of aradiation-based treatment device, according to example embodiments.

FIG. 4 illustrates an example radiation-based treatment deviceconfigured as a direct exposure device for providing fractionaltreatment, according to certain embodiments of the present disclosure.

FIGS. 5A and 5B illustrate a 3-D side view and an end tip view,respectively, of an example radiation engine for use in the directexposure laser treatment device shown in FIG. 4, according to an exampleembodiment.

FIG. 6 illustrates an exploded view of the example laser treatmentdevice shown in FIG. 5.

FIG. 7 illustrates an example electrical schematic of laser pulsingelectronics for controlling the pulsing of the edge emitting laser diodeof the example direct exposure laser treatment device shown in FIGS.5-7.

FIGS. 8A-8J illustrates example patterns of treatment spots and exampleglide directions and patterns for use with the device of the presentdisclosure, according to certain embodiments.

FIG. 9 shows a three-dimensional cross-section of a volume of skin forillustrating the process of a non-ablative fractional treatment.

FIG. 10 illustrates a simplified cross-sectional side view of an exampledirect exposure embodiment that includes an edge emitting laser diodeand a window in contact with the skin.

FIG. 11 illustrates a simplified cross-sectional side view of an exampledirect exposure embodiment that includes an edge emitting laser diodeand a window offset from the skin.

FIG. 12 illustrates a simplified cross-sectional side view of an exampledirect exposure embodiment that includes an edge emitting laser diodeseparated from the skin by only an air gap.

FIG. 13 illustrates a simplified cross-sectional side view of an exampledirect exposure embodiment that includes an edge emitting laser diodehaving a covering film and separated from the skin by only an air gap.

FIG. 14 illustrates a simplified cross-sectional side view of an exampledirect exposure embodiment that includes multiple edge emitting laserdiodes and a window in contact with the skin.

FIG. 15 illustrates a simplified cross-sectional side view of an exampleindirect exposure embodiment that includes an edge emitting laser diodeand a downstream concave lens.

FIG. 16 illustrates a simplified cross-sectional side view of an exampleindirect exposure embodiment that includes an edge emitting laser diodeand a downstream ball lens.

FIGS. 17A-17C illustrate the asymmetrical divergence of a beam emittedfrom an edge emitting laser diode, in embodiments in which the proximitygap spacing is extremely small.

FIGS. 18A-18C illustrate the asymmetrical divergence of a beam emittedfrom an edge emitting laser diode, in embodiments with a largerproximity gap spacing.

FIG. 19A-19B illustrates smearing or blurring of a treatment spot due tomovement of the device across the skin during the treatment pulse.

FIG. 20 is a plot of a detected wavelength profile of laser radiationreceived at a target surface from an example edge emitting laser diode.

FIGS. 21A and 21B illustrate example dimensions for a treatment spot andcorresponding MTZ generated by an edge emitting laser diode configuredfor direct exposure and/or close proximity radiation, according certainembodiments.

FIGS. 22A and 22B illustrate a configuration and example treatment spotarray, respectively, for a device including a laser diode bar as theradiation source, according to certain embodiments.

FIGS. 23A and 23B illustrate a configuration and example treatment spotarray, respectively, for a device including multiple laser diode bars asthe radiation source, according to certain embodiments.

FIGS. 24A and 24B illustrate a configuration and example treatment spot,respectively, for a device including a high fill-factor laser diode baras the radiation source, according to certain embodiments.

FIGS. 25 and 26 illustrate components of an example embodiment of adevice in which the radiation source is laser diode bar including anarray of 19 laser emitters that emit an array of beams to generate anarray of treatment spots in each pulse.

FIG. 27 illustrates an example direct exposure configuration of a deviceincluding a single-beam-source VCSEL laser as the radiation source,according to certain embodiments.

FIG. 28 illustrates an example arrangement of micro-emitters forming asingle-beam-source VCSEL laser, according to an example embodiment.

FIG. 29 illustrates an example indirect exposure arrangement of asingle-beam-source VCSEL laser and downstream optic (concave lens),according to certain embodiments.

FIG. 30 illustrates an example arrangement of micro-emitters andnon-active areas forming a multiple-beam-source VCSEL laser, accordingto an example embodiment.

FIG. 31 illustrates an example direct exposure configuration of a deviceincluding a multiple-beam-source VCSEL laser as the radiation source,according to certain embodiments.

FIG. 32 illustrates an example treatment spot array produced by anexample multiple-beam-source VCSEL laser having a two-dimensional arrayof emitter zones, according to certain embodiments.

FIG. 33 illustrates an example treatment spot array produced by anexample multiple-beam-source VCSEL laser having a one-dimensional arrayof emitter zones, according to certain embodiments.

FIG. 34 illustrates an example indirect exposure arrangement of amultiple-beam-source VCSEL laser and downstream optic (concave lensarray), according to certain embodiments.

FIG. 35 illustrates a block diagram of an example displacement-basedcontrol system, according to certain embodiments.

FIG. 36 illustrates a flowchart of an example method for controlling adevice using a displacement-based control system, while the device isused either in a gliding mode or a stamping mode, according to certainembodiments.

FIG. 37 illustrates an example single-pixel displacement sensor for usein a displacement-based control system, according to certainembodiments.

FIG. 38 illustrates another example single-pixel displacement sensor foruse in a displacement-based control system, according to certainembodiments.

FIG. 39 illustrates yet another example single-pixel displacement sensorfor use in a displacement-based control system, according to certainembodiments.

FIG. 40 illustrates a pair of experimental data plots for an embodimentof an optical displacement sensor being scanned above the skin surfaceof a human hand.

FIG. 41 represents an example plot of a signal generated by a detectoras a displacement sensor is moved across the skin of a human hand.

FIG. 42 illustrates three data plots: a raw signal plot, filtered signalplot, and a intrinsic skin feature detection plot, for detecting skinfeatures based on signals from a displacement sensor, according tocertain embodiments.

FIG. 43 illustrates a more specific example of the general method ofFIG. 36 for controlling a device using a displacement-based controlsystem, according to certain embodiments.

FIG. 44 illustrates an example multi-pixel imaging correlation sensor,of the type used in optical mice for computer input, for detectingdisplacement along the skin, according to certain embodiments.

FIG. 45 illustrates an example method for controlling device using adisplacement-based control system that employs a multi-pixeldisplacement sensor, while device is used either in a gliding mode or astamping mode, according to certain embodiments.

FIGS. 46A-46G illustrate example embodiments of a roller-based sensorthat may be used a displacement sensor, or a motion/speed sensor, orboth, for use in certain embodiments.

FIG. 47 illustrates an example method for executing a treatment sessionfor providing treatment (e.g., fractional light treatment) to a userwith certain embodiments of the device.

FIGS. 48-49 illustrate an example optical eye safety sensor, accordingto certain embodiments.

FIGS. 50A and 50B illustrate the local surface normal directions forexample corneas of different shapes.

FIG. 51 illustrates an example multi-sensor control/safety system thatincludes one or more eye safety sensors and one or more skin contactsensors arranged on or near device application end, according to certainembodiments.

FIG. 52 illustrates an example method for controlling a device using amulti-sensor control/safety system, according to certain embodiments.

FIG. 53 illustrates an example method for calibrating an eye safetysensor for one or multiple users, according to certain embodiments.

FIG. 54 shows another embodiment of a radiation-based treatment device.

FIG. 55 illustrates an example operational schematic of the exampledevice shown in FIG. 54, according to certain embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

Some embodiments of the disclosure may be understood by referring, inpart, to the following description and the accompanying drawings, inwhich like reference numbers refer to the same or like parts.

FIG. 1 illustrates various components of an example held-heldradiation-based treatment device 10, according to certain embodiments.Radiation-based treatment device 10 may include a radiation engine 12including a radiation source 14 configured to generate an energy beam60, optics 16 for conditioning and/or delivering the energy beam 60 to atreatment area of skin 40, control systems 18, one or more powersupplies 20, and/or one or more fans 34.

As discussed above, “direct exposure” embodiments of device 10 may omitoptics 16 such that no significant optics are provided between radiationsource 14 and the skin surface, thus providing direct radiation of theskin. Further, as discussed above, in some direct exposure embodiments,the emitting surface of radiation source 14 is located in closeproximity (within 10 mm) of the skin-contacting surface of the treatmenttip of the device or target tissue 40.

In some embodiments, the main components of device 10 may besubstantially self-contained in a held-held structure or outer housing24. Held-held housing 24 may define an application end (or “treatmenttip”) 42 configured to be placed in contact with the skin (or othertarget surface) during treatment of a treatment area of skin 40.Application end 42 may include or house various user interfaces,including the treatment delivery interface for delivering energy beam 60to the user, as well as one or more sensors 26 for detecting variouscharacteristics of the skin (or other surface) and/or energy deliveredby device 10. In some embodiments, application end 42 may include anaperture or window 44 through which the laser beam is delivered to thetarget surface, or alternatively, an optical element 16 (e.g., a lens)may be located at application end 42 and configured for direct contactor close proximity with the skin during treatment.

Device 10 may include any other components suitable for providing any ofthe functionality discussed herein or other related functionality knownto one of ordinary skill in the art.

Radiation engine 12 may include one or more radiation sources 14, suchas one or more lasers, LEDs, and/or flashlamps, ultrasound devices, RFdevices, or microwave emitters, for example. Embodiments includinglasers as the radiation source 14 may include any type or types oflasers, e.g., one or more edge emitting laser diodes (single emitteredge emitting laser diodes or multiple emitter edge emitting laserdiodes), laser diode bars, VCSEL lasers (Vertical Cavity SurfaceEmitting Lasers), CO2 lasers, Erbium YAG lasers, pulsed dye lasers,fiber lasers, other types of lasers, or any combination thereof.

Radiation source 14 may include one or more beam source, each operableto generating a beam for delivery to the skin. In some embodiments,radiation source 14 is a laser having exactly one beam source forgenerating a single beam, for example (a) a single-emitter edge emittinglaser diode that generates a single beam, (b) a multi-emitter edgeemitting laser diode that generates a single collective beam, e.g., asdescribed in co-pending U.S. Provisional Patent Application 61/594,128,the entire contents of which are hereby incorporated by reference, (c) alaser diode bar with high fill factor to generate a single collectivebeam or single beam with spatial modulation of its energy profile, e.g.,as discussed below, or (d) a VCSEL laser having multiple emitters thattogether act as a single beam source (i.e., a single “micro-emitterzone”) to generate a single combined beam. Item (b) “a multi-emitteredge emitting laser diode that generates a single collective beam”refers to an integral or monolithic laser diode structure havingmultiple emitter junctions formed on a substrate (such as, for example,a “multiple quantum well” (MQW) laser diode), and is thus distinguishedfrom a laser diode bar.

In other embodiments, radiation source 14 is a laser having multiplebeam sources for generating multiple discrete beams, for example (a) anlaser diode bar having multiple emitters, each generating a singlediscrete beam, or (b) a VCSEL laser having multiple micro-emitter zones(with one or more emitter per zone), with each micro-emitter zone actingas a discrete beam source to generate a single beam discrete from theothers. Such multiple beam sources may be arranged in a row, atwo-dimensional array, or otherwise.

In some embodiments, the beam emitted from each beam source diverges inat least one direction. For example, in embodiments including asingle-beam source edge emitting laser diode or multi-beam source laserdiode bar, the beam emitted from each beam source may diverge in both afast axis and a slow axis. Thus, in such embodiments, if the deviceincludes no optics downstream of the beam source(s), the energy beam(s)exit the application end of the device, and reach the target surface asan asymmetrically diverging beam. Further, in embodiments including aVCSEL laser, the emitted beam or beams may diverge symmetrically in bothaxes, e.g., by about 15 degrees.

As discussed below, the divergence of energy beams delivered by suchembodiments of device 10 may provide an aspect of eye-safety. In someembodiments, the arrangement of radiation source 14 and/or thedivergence of the beam(s) emitted from the light source may provideClass 1M or better eye safety classification per the IEC 60825-1standard, as discussed below.

In some embodiments, radiation source 14 may be configured for and/oroperated at any suitable wavelength to provide the desireddermatological treatment. For example, radiation source 14 may be alaser configured for and/or operated at a wavelength that is absorbed bywater in the skin, e.g., between 1400 nm and 2000 nm, e.g., for certainphotothermolysis or other treatments. In some embodiments, radiationsource 14 may be a laser configured for and/or operated at a wavelengthof between 1400 nm and 1550 nm, e.g., for acne treatment or certainfractional non-ablative skin treatments, e.g., skin rejuvenation orresurfacing, wrinkle treatment, or treatment of pigmented legions (e.g.,age spots, sun spots, moles, etc.). In other embodiments, radiationsource 14 may be a laser configured for and/or operated at a wavelengthof between 1700 nm and 1800 nm, e.g., for sebaceous gland relatedtreatment like acne. In still other embodiments, radiation source 14 maybe a laser configured for and/or operated at a wavelength of about 1926nm, e.g., for pigmented lesion treatment like solar lentigo. As anotherexample, radiation source 14 may be a laser configured for and/oroperated at a wavelength of about 810 nm for providing hair removaltreatment or melanin-based treatments. In some embodiments that includemultiple beam sources, different beam sources may emit light atdifferent wavelengths. For example, a device may include one or morefirst beam sources that emit a wavelength of about 1400 nm-1550 nm andone or more second beam sources that emit a wavelength of about 1926 nm.As another example, the wavelength may be in the UV (e.g., such as toeffect DNA or micro-organisms), may be in the visible spectrum (e.g.,such as to affect melanin, hemoglobin, oxyhemoglobin, or photosensitiveelements like mitochondria or fibroblasts) or in the IR spectrum (e.g.,such as to affect melanin, water, lipids). Likewise, the radiation maybe in the ultrasound spectrum (e.g., such as to perform focusedultrasound fractional skin rejuvenation or tightening) or in the radiofrequency spectrum (e.g., such as to perform fractional or bulkheating).

Radiation source 14 may be configured for or operated at any suitableenergy or power level. For example, in some embodiments, radiationsource 14 may emit a total energy of between about 2 mJ and about 30 mJper beam (i.e., per treatment spot). For example, radiation source 14may emit between about 5 mJ and about 20 mJ per beam. In particularembodiments, radiation source 14 emits about 15 mJ per beam.

Further, radiation source 14 may deliver continuous wave (CW) radiation,pulsed radiation, or in any other manner, depending on the particularembodiment, application, or device setting. For the purposes of thisdisclosure, pulsed or continuous wave radiation refers to the radiationdelivered out of application end 42 of device 10. Thus, radiation may bepulsed either by pulsing the radiation source 14, by intermittentlyblocking the energy beam emitted by radiation source 14, or otherwiseintermittently enabling and disabling the delivery of radiation out ofapplication end 42.

In some embodiments, device 10 controls radiation source 14 to provideCW or quasi-CW radiation, e.g., for bulk heating skin tightening, hairremoval, or acne treatment. In other embodiments, device 10 providespulsed radiation (e.g., by controlling pulsing radiation source 14, byintermittently blocking the energy beam emitted by radiation source 14,or otherwise), e.g., for fractional treatment. For example, in someembodiments, device 10 may be a laser-based device configured tosequentially deliver a series of laser beams to the treatment area 40 togenerate treatment spots that are spaced apart from each other by areasof non-irradiated skin between the adjacent treatment spots, to providea fractional treatment to the skin. Such embodiments may utilize anysuitable pulse parameters, e.g., pulse rate or frequency, pulse on time,pulse off time, duty cycle, pulse profile, etc. In some embodiments,radiation source 14 may be pulsed at a rate between 0.5 and 75 Hz. Forexample, radiation source 14 may be pulsed at a rate between 2 and 30Hz. In particular embodiments, radiation source 14 may be pulsed at arate between 10 and 20 Hz, e.g., about 15 Hz. The energy per pulse on agiven treatment spot can be achieved by a single pulse or by multiplerepetitive pulses.

As used herein, a “pulse” may include both (a) a single, continuousburst of radiation, and (b) one or more higher-frequency pulses atsubstantially the same location (i.e., with substantially overlappingareas of irradiation at the target plane), sometimes referred to as amodulated pulse, pulse train, or super pulse. If the time intervalbetween the pulses in a pulse train is shorter than the relaxation timeof the mechanism of action (e.g., shorter than the thermal relaxationtime of a photothermolysis chromophore target), then the pulse train candeliver substantially similar results as a single longer pulse.

As used herein, a “treatment spot” means a contiguous area of skinirradiated by a beam source—during a continuous period of irradiation orduring a pulse (as defined above)—to a degree generally sufficient toprovide a desired treatment in the skin at that location. For some typesof beam source, including laser beam sources for example, the boundariesof the treatment spot are defined by the “1/e² width,” i.e., thetreatment spot includes a contiguous area of the skin surface that isirradiated by a radiation intensity equal to at least 1/e² (or 0.135)times the maximum radiation intensity at any point on the skin surface.A treatment spot may include the full extent of the surface (or volume)irradiated. A treatment spot may include the full extent of the tissuebeing influenced by the irradiation, which may be smaller than theirradiated area or volume, or may be larger (e.g., due to thermalconductivity). Further, reference to a treatment spot “on the skin” orsimilar language refers to radiation pattern on the skin which generallyproduces a radiation pattern within the skin, whether or not it producesa treatment effect on the surface of the skin.

A treatment spot includes any increased areas due to smearing, blurring,or other elongation in any one or more direction due to movement of thedevice across the skin, whether the radiation source is providing pulsedor continuous wave (CW) radiation. Thus, if the device is moved acrossthe skin during CW radiation (e.g., in a gliding mode operation), atreatment spot may be many times larger than the size of theinstantaneous irradiated area of skin. If the device is moved across theskin during pulsed radiation (e.g., in a gliding mode operation), atreatment spot may be, for example, 10% to 500% larger than the size ofthe instantaneous irradiated area of skin, depending on a number offactors.

Certain embodiments of device 10 include one or more optics 16downstream of radiation source 14 for directing or treating the beam 60emitted from radiation source 14 before reaching the target surface.Optics 16 may allow for radiation source 14 to be positioned at anydesired distance from the application end 42 of the device that contactsthe skin during treatment (and thus at any desired distance from thetarget surface). Embodiments of device 10 that include optics 16downstream of radiation engine 12 are referred to herein as “indirectexposure” embodiments.

Optics 16 may include any number and types of optical elements, e.g.,lenses, mirrors, and other elements, for delivering the light generatedby radiation engine 12 to the treatment area 40 and, if desired, fortreating the beam, such as adjusting the treatment spot 62 size,intensity, treatment spot location, angular distribution, coherence,etc.

As used herein, an “optic” or “optical element” may mean any elementthat deflects a light beam, influences the angular distribution profile(e.g., angle of convergence, divergence, or collimation) of a beam in atleast one axis, influences the focus of the beam in at least one axis,or otherwise affects a property of the radiation. Thus, optics includemirrors and other reflective surfaces, lenses, prisms, light guides,gratings, filters, etc. For the purposes of this disclosure, optics donot generally include planar or substantially planar transmissiveelements such as transmissive windows or films, such as those that serveas transmissive aperture that protect internal components.

Other embodiments of device 10 do not include any optics 16 downstreamof radiation source 14 for affecting or treating the beam. Suchembodiments are referred to herein as “direct exposure” embodiments.Some direct exposure devices may include a window (e.g., to protectradiation source 14 and/or other internal components of device 10) thatdoes not substantially affect the beam 60. In some embodiments (e.g.,certain embodiments including one or more edge emitting laser diodes asthe radiation source 14), the radiation source 14 may be positioned veryclose to the application end 42 of the device that contacts the skinduring treatment (and thus very close to the target surface). Forexample, in some direct exposure devices, the radiation source 14 may bepositioned such that the emitting surface of the radiation source 14 isless or equal to 10 mm from the skin when the application end 42 isplaced in contact with the skin, referred to herein as close proximityembodiments.

Control systems 18 may be configured to control one or more componentsof device 10 (e.g., radiation engine 12, fans 34, displays 32, etc.).Control systems 18 may include, for example, any one or more of thefollowing: a radiation source control system for controlling aspects ofthe generation, treatment, and delivery of energy beams 60 to the user;a displacement-based control system for controlling aspects of device 10based on the determined displacement of device 10 across to the skin(e.g., as device is glided across the skin during treatment), e.g.,relative to a prior treatment position; a temperature control system; aneye safety control system to help prevent exposure of the eyes (e.g.,the corneas) to the treatment radiation (an eye safety control systemmay be omitted in embodiments in which the laser radiation emitted fromdevice 10 is inherently eye-safe, e.g., certain direct exposureembodiments of device 10); and/or a battery/power control system.

Control systems 18 may include one or more sensors 26 and/or userinterfaces 28 for facilitating user interaction with device 10, andcontrol electronics 30 for processing data (e.g., from sensors 26 and/oruser interfaces 28) and generating control signals for controllingvarious components of device 10. Control electronics 30 may include oneor more processors and memory devices for storing logic instructions oralgorithms or other data. Memory devices may include any one or moredevice for storing electronic data (including logic instructions oralgorithms), such as any type of RAM, ROM, Flash memory, or any othersuitable volatile and/or non-volatile memory devices. Logic instructionsor algorithms may be implemented as software, firmware, or anycombination thereof. Processors may include any one or more devices,e.g., one or more microprocessors and/or microcontrollers, for executinglogic instructions or algorithms to perform at least the variousfunctions of device 10 discussed herein. Control electronics 30 mayinclude exclusively analog electronics or any combination of analog anddigital electronics.

Control systems 18 may control components or aspects of device 10 basedon feedback from sensors 26, user input received via user interfaces 28,and/or logic instructions/algorithms. For example, in some embodiments,control systems 18 may control the operation of radiation engine 12based at least on feedback from a displacement sensor. Thus, forexample, control systems 18 may control radiation engine 12 based onsignals from a displacement sensor indicating that device 10 ortreatment tip 42 has been translated a certain distance across treatmentarea 40 from a prior treatment position.

Control systems 18 may include, for example, a radiation source controlsystem for controlling aspects of the generation, treatment, anddelivery of energy beams 60 to the user; a displacement-based controlsystem for controlling aspects of device 10 based on the determineddisplacement of device 10 across the skin (e.g., as device is glidedacross the skin during treatment), e.g., relative to a prior treatmentposition; a temperature control system; an eye safety control system tohelp prevent exposure of the eyes (e.g., the cornea) to the treatmentradiation; and a battery/power control system. Such control systems 18are discussed in greater below with reference to FIG. 2 and subsequentfigures.

More specifically, control systems 18 may be configured to control oneor more operational parameters of device 10. For example, controlsystems 18 may control the treatment level (e.g., low power level,medium power level, or high power level) or treatment mode (e.g.,gliding mode vs. stamping mode; or rapid-pulse mode vs. slow-pulse mode;or initial treatment mode vs. subsequent treatment mode; etc.), thestatus of radiation source 14 (e.g., on/off, pulse-on time, pulse-offtime, pulse duty cycle, pulse frequency, temporal pulse pattern, etc.),parameters of the radiation (e.g., radiation wavelength, intensity,power, fluence, etc.), the configuration or operation of one or moreoptical elements (in certain indirect exposure embodiments), and/or anyother aspects of device 10.

Sensors 26 may include any one or more sensors or sensor systems forsensing or detecting data regarding device 10, the user, the operatingenvironment, or any other relevant parameters. For example, as discussedin greater detail below with respect to FIG. 2, sensors 26 may includeone or more of the following types of sensors: (a) one or moredisplacement sensor for determining the displacement of device 10relative to the skin, (b) one or more motion/speed sensor fordetermining the speed, rate, or velocity of device 10 moving (“gliding”)across the skin, (c) one or more skin-contact sensor for detectingproper contact between device 10 and the skin, (d) one or more pressuresensor for detecting the pressure of device 10 pressed against the skin,(e) one or more temperature sensor for detecting the temperature of theskin, a region of the skin, and/or components of device 10, (f) one ormore radiation sensor for detecting one or more parameters of radiation(e.g., intensity, fluence, wavelength, etc.) delivered or indicative ofdelivered to the skin, (g) one or more color/pigment sensor fordetecting the color or level of pigmentation in the skin, (h) one ormore eye safety sensor for preventing unwanted eye exposure to lightfrom radiation source 14, (i) one or more dwell sensor for detecting ifthe device is stationary or essentially stationary with respect to theskin, (j) one or more roller-type sensors for detecting the displacementand/or glide speed of the device, and/or any (k) other suitable types ofsensors.

User interfaces 28 may include any systems for facilitating userinteraction with device 10. For example, user interfaces 28 may includebuttons, switches, knobs, sliders, touch screens, keypads, devices forproviding vibrations or other tactile feedback, speakers for providingaudible instructions, beeps, or other audible tones; or any othermethods for receiving commands, settings, or other input from a user andproviding information or output to the user. User interfaces 28 may alsoinclude one or more displays 32, one or more of which may be touchscreens for receiving user input. One or more user interfaces 28 orportions thereof may be included in a separate housing from thetreatment device, such as in a smart charging dock or a personalcomputer, and the treatment device may communicate with the separatehousing via hardwire (such as a cable or jack), wireless methods (suchas infrared signals, radio signals, or Bluetooth), or other suitablecommunication methods.

Power supplies 20 may include any one or more types and instances ofpower supplies or power sources for generating, conditioning, orsupplying power to the various components of device 10. For example,power supplies 20 may comprise one or more rechargeable ornon-rechargeable batteries, capacitors, super-capacitors, DC/DCadapters, AC/DC adapters, and/or connections for receiving power from anoutlet (e.g., 110V wall outlet). In some embodiments, power supplies 20include one or more rechargeable or non-rechargeable batteries, e.g.,one or more Li containing cells or one or more A, AA, AAA, C, D,prismatic, or 9V rechargeable or non-rechargeable cells.

Control Systems

FIG. 2 illustrates example components of control systems 18 forcontrolling aspects of device 10, according to certain embodiments.Control systems 18 may include control electronics 30, sensors 26, userinterfaces 28, and a number of control subsystems 52. Control subsystems52 are configured to control one or more components of device 10 (e.g.,radiation engine 12, fans 34, displays 32, etc.). In some embodiments,control subsystems 52 may include a radiation source control system 130,a displacement-based control system 132, a user interface control system134, a temperature control system 136, a battery/power control system138, and/or any other suitable control systems for controlling any ofthe functionality disclosed herein. User interface control system 134may include a user interface sensor control system 140 and a userinput/display/feedback control system 142.

Each control subsystem 52 may utilize any suitable control electronics30, sensors 26, user interfaces 28, and/or any other components, inputs,feedback, or signals related to device 10. Further, any two or morecontrol systems may be at least partially integrated. For example, thefunctionality of control systems 130-138 may be at least partiallyintegrated, e.g., such that certain algorithms or processes may providecertain functionality related to multiple or all control systems130-138.

Each control subsystem 52 (e.g., subsystems 130-138) may be configuredto utilize any suitable control electronics 30, sensors 26, and userinterfaces 28. In some embodiments, control electronics 30 may be sharedby more than one, or all, control subsystems 52. In other embodiments,dedicated control electronics 30 may be provided by individual controlsubsystems 52.

Control electronics 30 may include one or more processors 150 and memorydevice 152 for storing logic instructions or algorithms 154 or otherdata. Memory devices 152 may include any one or more device for storingelectronic data (including logic instructions or algorithms 154), suchas any type of RAM, ROM, Flash memory, or any other suitable volatileand/or non-volatile memory devices. Logic instructions or algorithms 154may be implemented as hardware, software, firmware, or any combinationthereof. Processors 150 may include any one or more devices, e.g., oneor more microprocessors and/or microcontrollers, for executing logicinstructions or algorithms 154 to perform at least the various functionsof device 10 discussed herein. Control electronics 30 may includeexclusively analog electronics or any combination of analog and digitalelectronics.

Sensors 26 may include any one or more sensors or sensor systems forsensing or detecting data regarding device 10, the user, the operatingenvironment, or any other relevant parameters. For example, sensors 26may include one or more of the following types of sensors:

(a) At least one displacement sensor 100 for detecting, measuring,and/or calculating the displacement of device 10 relative to the skin40, or for generating signals from which the displacement is determined.In some embodiments, e.g., as discussed below with reference to FIGS.37-43, displacement sensor 100 may be a single-pixel sensor configuredto determine a displacement of device 10 by identifying and countingintrinsic skin features in the skin. In other embodiments, e.g., asdiscussed below with reference to FIGS. 44-45, displacement sensor 100may be a multiple-pixel sensor, such as a mouse-type optical imagingsensor utilizing a two-dimensional array of pixels.

In other embodiments, e.g., as discussed below with reference to FIGS.46A-46F, displacement sensor 100 may be a roller-type sensor 118 inwhich the amount of roller rotation indicates the linear displacement ofthe device. For example, a roller-type sensor displacement sensor 100may include a mechanical roller having one or more indicia, a detectiondevice (e.g., an optical or other scanner) for identifying such indiciaas they roll past the detection device, and processing electronics fordetermining the displacement of device 10 based on the detection of suchindicia. In some embodiment, the roller may also be actively driven by amotor to facilitate a gliding treatment.

In still other embodiments, displacement sensor 100 may comprise acapacitive sensor, as described below. Displacement sensor 100 may useany number of other devices or techniques to calculate, measure, and/orcalculate the displacement of device 10.

Displacement sensor 100 may be used for (i) detecting, measuring, and/orcalculating linear displacements of device 10 in one or more directions,(ii) detecting, measuring, and/or calculating the degree of rotationtravelled by device 10 in one or more rotational directions, or (iii)any combination thereof.

(b) At least one motion/speed sensor 102 for detecting, measuring,and/or calculating the rate, speed, or velocity of device 10 movingacross the treatment area 40 (the “manual glide speed”), or forgenerating signals from which the manual glide speed is determined;

(c) At least one skin-contact sensor 104 for detecting contact betweendevice 10 and the skin or treatment area 40. For example, device 10 mayinclude one or more capacitive contact sensors 104 for detecting contactwith the user's skin.

(d) At least one pressure (or force) sensor 106 for detecting thepressure (or force) of device 10 against the skin or treatment area 40.

(e) At least one temperature sensor 108 for detecting the temperature ofthe treatment area 40, a region of the treatment area 40 (such as thetreatment spot 62 before, during, and/or after treatment), components ofdevice 10, or other object.

(f) At least one radiation sensor 110 for detecting levels or otherparameters of radiation delivered to the treatment area 40 or indicativeof the radiation delivered to the treatment area 40 (e.g., per lightpulse, per individual beam/treatment spot, per delivered array ofscanned beams/treatment spots 62, per a specific number of individualdelivered beams/treatment spots 62 or scanned arrays of beams/treatmentspots 62, or per a specific time period). For example, device 10 mayinclude a photodiode to measure the pulse duration of the treatmentbeam.

(g) At least one color/pigment sensor 112 for detecting the color orlevel of pigmentation in the treatment area 40.

(h) At least one eye safety sensor 114 for helping to prevent unwantedeye exposure to light from the treatment radiation source 14. Exampleeye safety sensors 114 are discussed below with reference to FIGS.48-51.

(i) At least one dwell sensor 116 for detecting whether device 10 isstationary or essentially stationary with respect to the skin.

(j) At least one roller-based sensor 118 that may be used as adisplacement sensor 100, a motion/speed sensor 102, a dwell sensor 116or all, for detecting signals indicative of the displacement of device10, the manual glide speed of device 10, or stationary status of device10, or both.

(k) any other type of sensors.

User interfaces 28 may include any systems for facilitating userinteraction with device 10, e.g., displaying data or providing feedbackto a user visually and/or audibly, and/or palpably (e.g., viavibration), and receiving commands, selections, or other input from theuser. For example, user interfaces 28 may include one or more displays32 (one or more of which may be interactive touch screens), one or moremanual devices 160 (e.g., buttons, switches, knobs, sliders, touchscreens, keypads, etc.), one or more speakers 162, and/or any otherdevices for providing data, information, or feedback to a user orreceiving input or information from a user.

Control subsystems 52 may be configured to control one or morecontrollable operational parameters of device 10, based on feedback fromsensors 26, user input received via user interfaces 28, and/or executionof logic instructions/algorithms 154. As used herein, “controllableoperational parameters” may include any aspects or parameters of device10 that may be controlled by any of control subsystem 52.

For example, one or more control subsystems 52 may control any aspectsof the operation of radiation source 14, such as for example:

(a) selecting and/or switching the treatment mode (discussed below),

(b) controlling the on/off status of radiation engine 12 (which mayinvolve controlling individual light sources separately or as a group),and the timing of such on/off status: e.g., pulse-on time (pulse width),pulse-off time, pulse duty cycle, pulse frequency, temporal pulsepattern, etc.,

(c) controlling one or more parameters of the radiation: e.g.,wavelength, intensity, power, fluence, etc. (e.g., by controlling thepower supplied to radiation engine 12), and/or

(d) controlling any other aspect of radiation source 14.

Control subsystems 52 (e.g., control systems 130-138) may controlcomponents or aspects of device 10 based on feedback from sensors 26,user input received via user interfaces 28, and/or logicinstructions/algorithms 154. For example, in some embodiments, controlsystem 130 may control the operation of radiation source 14 based onfeedback from a displacement sensor 100 and skin contact sensor(s) 104.As another example, control system 130 may control the operation ofradiation source 14 based on feedback from a displacement sensor 100,skin contact sensors 104, and an eye safety sensor 114. In otherembodiments, control system 130 may control the operation of radiationsource 14 based on feedback from a glide rate sensor 102 and skincontact sensor(s) 104. In other embodiments, control system 130 maycontrol the operation of radiation source 14 based on feedback from adwell sensor 116 and skin contact sensor(s) 104. In other embodiments,control system 130 may control the operation of radiation source 14based on feedback from both a displacement sensor 100 or dwell sensor116 and a glide rate sensor 102, in addition to one or more othersensors 104-116.

FIG. 3 illustrates a functional block diagram of an example device 10,according to certain example embodiments. Device 10 may include variouscomponents contained in a housing 24, including a radiation engine 12,optics 16 (omitted in certain embodiments, as discussed herein), controlsystems 18, displays 32, a power source (in this example, a battery) 22,various sensors 26, and a cooling fan 34 (omitted in certainfully-solid-state embodiments, as discussed herein).

Radiation engine 12 may include one or more radiation sources 14 (e.g.,one or more lasers), a heat sink or other cooling system 36, and in someembodiments, optics 16 (e.g., a fast-axis cylindrical lens coupled to alaser package and positioned immediately downstream of an edge emittinglaser diode).

As discussed above, optics 16 (which are excluded in direct exposureembodiments, as discussed herein) may include any number and types ofoptical elements, e.g., lenses, mirrors, and other elements, fordelivering (e.g., directing and/or routing) an energy beam 60 fromradiation engine 12 to the treatment area 40 and/or for treating thebeam 60, such as adjusting the treatment spot size, intensity, treatmentspot location, angular distribution, coherence, etc.

In the illustrated embodiment, device 10 may include a displacementsensor 100, skin contact sensor(s) 104, and/or an eye safety sensor 114(and/or other sensors discussed herein). Displacement sensor 100 maymonitor the lateral displacement of device 10 relative to the skin,e.g., as device 10 is moved across the skin in a gliding mode orstamping mode of operation. Skin contact sensors 104 may determinewhether device 10, in particular an application end (or “treatment tip”)42, is in contact with or sufficiently close to the skin for providingtreatment to the user. Eye safety sensor 114 may determine whether theapplication end 42 of device 10, e.g., a treatment window 44 or outputaperture, is positioned over the skin or the cornea, such that device 10be controlled (e.g., radiation source 14 turned off) when the cornea isdetected, in order to prevent unintended exposure of the cornea.

As discussed above, control systems 18 may include any suitablesubsystems for controlling the various components and aspects of device10. In this example, control systems 18 include a radiation sourcecontrol system 130, a displacement-based control system 132, a userinterface control system 134, a temperature control system 136, and abattery/charger control system 138. Each control subsystem 130-138 mayutilize or interact with control electronics 30, sensors 26 (e.g.,sensors 100, 104, and/or 114), and user interfaces 28.

Radiation source control system 130 may monitor and control variousaspects of radiation source 14. For example, system 130 may turnradiation source 14 on and off, and monitor and control the intensity ofgenerated light or other radiation (e.g., by controlling the current toradiation source 14). As another example, in embodiments orconfigurations in which radiation source 14 is pulsed, system 130 maymonitor and/or control the pulse frequency, pulse on time, pulse offtime, pulse duration, pulse wave profile, duty cycle, or any otherparameters of the pulsed delivery. As another example, system 130 maymonitor the temperature of laser radiation source 14, which data may beused by temperature control system 136, e.g., for controlling fan 34. Inaddition, system 130 may turn radiation source 14 off, or reduce powerto radiation source 14 based on the monitored temperature of laserradiation source 14 (e.g., to prevent overheating). Radiation sourcecontrol system 130 may utilize data or signals from any other controlsubsystems (e.g., user interface control system 134, temperature controlsystem 136, and/or battery/charger control system 138) for controllingaspects of laser radiation source 14.

User interface control system 134 may include a user interface sensorcontrol system 140 for monitoring and controlling displacement sensor100, skin contact sensors 104, and/or eye safety sensor 114. Forexample, system 134 may receive signals detected by each sensor, andsend control signals to each sensor. User interface control system 134may include a user input/display/feedback control system 142 formonitoring and controlling user interfaces 28 and displays 32. Forexample, system 134 may receive user input data from various userinterfaces 28, and control information communicated to the user viadisplays 32 (e.g., visually, audibly, and/or palpably). User interfacecontrol system 134 may communicate data or signals with, or otherwisecooperate with, other control subsystems, e.g., radiation source controlsystem 130, temperature control system 136, and/or battery/chargercontrol system 138.

Temperature control system 136 may be configured to monitor and controlthe temperature of one or more components of device 10, e.g., radiationsource 14, battery 20, etc. Thus, temperature control system 136 mayreceive data from one or more temperature sensors 108, and control oneor more fans 34 based on such data. In addition to controlling fan(s)34, temperature control system 136 may generate control signals forcontrolling radiation source 14, motor 120, etc. based on temperaturedata. For example, temperature control system 136 may communicatesignals to radiation source control system 130 to turn off or otherwisecontrol radiation source 14 to avoid overheating (or in response to adetected overheating) of such component(s), to maintain such componentswithin predefined performance parameters, or for any other purpose.Temperature control system 136 may communicate data or signals with, orotherwise cooperate with, radiation source control system 130, userinterface control system 134, and/or battery/charger control system 138.

Battery/charger control system 138 may be configured to monitor andcontrol the charging of battery 20. In some embodiments, multiplebatteries 20 are included in device 10. In some embodiments, battery 20may be removable from device 10, e.g., for replacement or as aconsumable element (e.g., with optionally a unique hardware design orelectronic encryption or other means to make proprietary). As shown inFIG. 3, device 10 may be configured for connection to a wall plug-incharger 170 and/or a charging stand 172 via control electronics 30, forcharging battery 20. System 138 may monitor the current charge and/ortemperature of battery 20, and regulate the charging of battery 20accordingly. Battery/charger control system 138 may communicate data orsignals with, or otherwise cooperate with, other control subsystems,e.g., user interface control system 134, temperature control system 136,and/or battery/charger control system 138. In other embodiments, e.g.,where power supply comprises one or more cells (e.g., size A, AA, AAA,C, D, prismatic, or 9V cells), battery/charger control system 138, wallplug-in charger 170, and charging stand 172 may be omitted. Otherembodiments may include a power cord connected to mains supply, anelectronic power supply, or other sources of power. Such embodiments maystill be substantially hand-held.

Device 10 may include a delivery end, referred to herein as applicationend 42, configured to be placed against the skin, in particulartreatment area 40. Application end 42 may include or house various userinterfaces, including the treatment delivery interface for deliveringbeams 60 to the user, as well as one or more sensors 26 for detectingvarious characteristics of the target surface and/or treatment deliveredby device 10. For example, in the illustrated embodiment, applicationend 42 provides an interfaces for displacement sensor 100, skin contactsensors 104, and/or eye safety sensor 114, allowing these sensors tointerface with the user's or patient's skin or tissue. In someembodiments, application end 42 provides a window 44 through which beams60 are delivered.

Operation of Device 10

As discussed above, device 10 is configured to deliver one or moreenergy beams 60 to a treatment area 40 to provide a desireddermatological treatment. Device 10 may deliver beam(s) 60 to generatevarious treatment patterns in the treatment area 40. For example,various treatment patterns may be generated by any combination of thefollowing: operating device 10 in a manual gliding mode, operatingdevice 10 in a stamping mode, providing continuous wave (CW) radiation,providing pulsed radiation, providing direct exposure radiation,providing indirect exposure radiation, providing close proximityradiation, providing remote proximity radiation, any other modes, or anycombination thereof.

Each energy beam 60 from device 10 may form an irradiated treatment spot(or “treatment spot”) 62 on the surface of the skin, and (in certainembodiments) a three-dimensional volume of thermally damaged skinextending below the surface of the skin, referred to herein as a microthermal zone (MTZ) 64. Each MTZ may extend from the skin surfacedownward into the skin, or may begin at some depth below the skinsurface and extend further downward into the skin, depending on theembodiment, device settings, or particular application. In embodimentsor situations in which the irradiated area on the skin moves across theskin during delivery of the radiation, referred to as “blurring” or“smearing” of the irradiated area (e.g., as caused by movement of thedevice during a gliding mode operation of device 10, wherein thedelivered beam 60 remains stationary with respect to the device housing24), the treatment spot 62 is defined as the collective area swept bythe moving irradiated area throughout a continuous (i.e., uninterrupted)period of radiation delivery to the skin at that location. Someembodiments may compensate for blur by tracking device motion across theskin and dynamically adjusting the location or direction of thedelivered beam 60 with respect to the device housing 24, or by theconfiguration of light sources or scanning modes, or in other ways.

In some applications, such as hair removal treatment, beams 60 maygenerate treatment spots 62 to cause thermal injury of hair follicles.In other applications, such as fractional treatment for example, beams60 (e.g., laser beams) may generate treatment spots 62 to cause thermalinjury to the skin, e.g., ablative or non-ablative lesions.

In some embodiments, device 10 is configured to be used in a “glidingmode” in which the device is manually dragged or glided across the skinwhile delivering continuous wave (CW) radiation or pulsed radiation tothe treatment area 40, e.g., to create continuous elongated treatmentspots 62 in the direction of gliding, or alternatively to create rows orarrays of discrete treatment spots 62 (spaced apart, touching, oroverlapping) in the direction of gliding.

In other embodiments, device 10 is configured to be used in a “stampingmode” in which device 10 is held relatively stationary at differentlocations on the skin. At each location on the skin, device 10 maydeliver one or more beams 60 to generate one or more correspondingtreatment spots 62 on the skin. Thus, device 10 may be positioned at afirst location, one or more treatment spots 62 may then be delivered tothe skin while device 10 is held relatively stationary, device 10 maythen be moved—e.g., by lifting and repositioning device 10, or bygliding device 10 across the surface of the skin—to a new location onthe skin, and one or more treatment spots 62 may then be generated atthat location (e.g., by automated or manual pulsing of the radiationsources(s) 14), and so on, in order to cover a treatment area 40 asdesired.

In some embodiments, device 10 may be configured to generate an array ofMTZs 62 in the skin that are laterally spaced apart from each other byvolumes of untreated (i.e., non-irradiated or less irradiated) skin,e.g., to provide a fractional treatment. For example, the applicationend 42 of device 10 may be manually moved across the surface of the skinduring a treatment session. Energy beams 60 may be pulsed during themovement of device 10 across the skin (in a gliding mode operation), orbetween intermittent movements of device 10 across the skin (in astamping mode operation). The skin's healing response, promoted by theareas of untreated skin between adjacent MTZs 64, may provide benefit inthe treatment area (e.g., skin resurfacing or rejuvenation, wrinkleremoval or reduction, etc.).

Direct Exposure and/or Close Proximity

As discussed above, some embodiments of device 10 are “direct exposuredevices” that do not include any optics 16 downstream of radiationsource(s) 14 for delivering or treating beam(s) 60. However, some directexposure devices may include a planar or substantially planar window 44(e.g., a thin sapphire or BK-7 like glass window or a thin film orequivalent) downstream of radiation source(s) 14, e.g., to protect theradiation source(s) and/or other internal components of the device.

In embodiments that use a relatively rapidly divergent beam source(e.g., edge emitting laser diodes, laser diode bars, and certainVCSELs), due to the rapid divergence of beam(s) 60 emitted from theradiation source(s) 14, the radiation source(s) 14 may be positionedvery close to the application end 42 of the device that contacts theskin during treatment (and thus very close to the skin surface). Forexample, in some direct exposure devices, the radiation source(s) 14 maybe positioned such that the emitting surface(s) of the radiationsource(s) 14 are arranged at less than or equal to 10 mm of the skinduring treatment, referred to herein as a close proximity configuration.In some embodiments, the emitting surface(s) of the radiation source(s)14 are arranged at a distance of less than or equal to 5 mm, 2 mm, 1 mm,500 μm, 200 μm, or even 100 μm from the surface of the skin when theapplication end 42 is placed in contact with the skin.

Some direct exposure embodiments of device 10 may be configured toprovide CW radiation in a gliding mode. For example, as discussed belowwith respect to FIGS. 24A and 24B, direct exposure embodiments of device10 including a high fill-factor laser diode bar 14C may be operated in aCW mode while the device is manually glided across the skin in adirection generally perpendicular to the elongated direction of thelaser diode bar, to generate a continuous elongated treatment spot 62 inthe manual glide direction, having a width generally corresponding tothe width of the laser diode bar. The device may be glided multipletimes across the skin at adjacent locations to cover a desired treatmentarea 40, e.g., to provide a hair removal treatment.

Other direct exposure embodiments of device 10 may be configured toprovide pulsed radiation in a gliding mode, e.g., to provide afractional treatment. For example, as discussed below, direct exposureembodiments of device 10 including one or more edge emitting laserdiodes, laser diode bars, or VCSELs may be operated in a pulsed mannerwhile the device is manually glided across the skin to generate agenerally one-dimensional or two-dimensional array of treatment spots 62for each glide of the device 10 across the skin. The device may beglided multiple times across the skin at adjacent locations and over thesame area to cover a desired treatment area 40, e.g., to provide afractional treatment.

Example Embodiment of Device 10

FIGS. 4-7 illustrate an example embodiment of device 10 configured as adirect exposure device for providing fractional treatment. As shown inFIG. 4, the example device 10 may include a laser engine 12 includingone or more lasers (e.g., one or more edge emitting laser diodes, laserdiode bars, or VCSELs) configured to emit one or more pulsed laser beams60, and one or more batteries 20, both housed in a device housing 24. Insome embodiments, laser engine 12 includes a single beam sourceconfigured to emit a single pulsed beam 60, e.g., an edge emitting laserdiode or a VCSEL configured to emit a single beam 60. In otherembodiments, laser engine 12 includes multiple beam sources configuredto emit multiple discrete pulsed beams 60, e.g., multiple edge emittinglaser diodes, an laser diode bar, multiple laser diode bars, multipleVCSELs, or a VCSEL configured to emit multiple discrete beams 60 (e.g.,as discussed below with reference to FIGS. 30-34), for example.

Battery or batteries 20 may include any number and type of batteries,e.g., A-sized or smaller batteries, or rechargeable or non-rechargeablecells (e.g., Li ion, lithium ferro phosphate, NiMH, NiCAD, or othercells), or any other type of battery.

Device 10 has an application end 42 configured to contact the user'sskin as device 10 is moved across the skin during a treatment session.In this embodiment, application end 42 is defined by a leading end oflaser engine 12, which projects from device housing 24. The applicationend 42 may include a laser treatment aperture 220 through which one ormore laser beam(s) 60 generated by the laser engine 12 are delivered tothe skin 40.

In addition, device 10 may include one or more sensors 26, e.g., any oneor more of the various types of sensors 26 disclosed herein. Forexample, device 10 may include one or more skin contact sensors 104, adisplacement sensor 100, a motion/speed sensor 102, a dwell sensor 116,and/or an eye safety sensor 114. The one or more sensors 26 may belocated at any suitable location(s) on device 10, e.g., at or nearapplication end 42. In some embodiments, device 10 includes a skincontact sensor 104 and a displacement sensor 100 configured to avoidunintentional exposure and/or overexposure of the skin (e.g., bypreventing stacking or overlapping of treatment spots 62). The skincontact sensor 104 and displacement sensor 100 may be provided by asingle combined contact/displacement sensor, or may be provided asseparate sensors. Such sensor(s) may be optical or capacitance-based oruse any other suitable means. Contact with the skin may be detected byanalyzing an amplitude of an optical reflectance or capacitance signalgenerated by the sensor. Further, dwelling of device 10 on the skin maybe detected by analyzing signal in the optical reflectance orcapacitance signal associated with application end 42 of device 10moving across the skin or by other suitable means. Because skin surfaceis not perfectly smooth and the manual moving of a device cannot achieveperfect steady motion, stiction (static friction) between device 10 andskin and/or other physical principles result in micro-displacement(non-lateral) between the sensor and the skin surface. For example, acapacitive sensor's signal is inversely proportional to the relativedistance between the sensor and the test surface. Any micro-displacementdue to natural stick-and-slip movement across the skin will result in atranslational signal on top of the nominal steady-state sensor signal.This signal may be analyzed to determine whether device 10 is movingacross the skin, or dwelling at the same location. Such analysis mayinclude any suitable algorithms, e.g., comparing the signal to one ormore threshold values.

In the example shown in FIG. 4, device 10 includes a manual power button200. Device 10 enables the delivery of beams to the skin in a pulsedmanner while power button 200 remains depressed by the user, and thesensor(s) 26 detect that device 10 is in proper contact with the skinand has translated, is moving with a certain velocity range, and/or isnot dwelling. In other embodiments, the power button may be a simpleon/off switch and the light pulsing is controlled only, for example, byone or more sensors and not the manual power button.

The specific user interface scheme, and the shape and size of the devicehousing 24 may be configured as desired. In some embodiments, the shapeand size of device housing 24 is easy to grip and includes a simple,conveniently located power button 200 and/or other user interfaces 28.In addition, the shape of device 10 may be ergonomic, and/or beconfigured to provide good visibility of the treatment area 40. Exampleshapes are pencil-like, pen-like, lipstick-like, organic shapes likepebbles, cigarette lighter-like, and numerous other shapes.

FIGS. 5A, 5B, and 6 illustrate details of an example laser engineassembly 12 for use in the example direct exposure fractional treatmentdevice of FIG. 4, according to certain embodiments. In particular, FIGS.5A and 5B illustrate an assembled view of the example laser engine 12,while FIG. 6 illustrates an exploded view of the various components ofdevice 10.

In some embodiments, the laser engine 12 may include an edge emittinglaser diode 14 directly mounted to a thermal reservoir heat sink 36 viaany suitable manner (e.g., via soldering, clamping, or adhesive) ormounted to one or more subcarriers (e.g., a ceramic, plated ceramic,copper block, etc) to provide electrical isolation and/or thermalconduction, for example. Electrical connection to the edge emittinglaser diode 14 may be made by wire bonding, soldering, clamping, orother suitable means between the edge emitting laser diode 14 and thesubcarrier(s), to the heat sink 36, or to other electrical connectionpoint(s) (e.g., a printed circuit board) in device 10. In someembodiments, the laser engine assembly 12 may include an edge emittinglaser diode chip mounted on a heat spreader, which is in turn mounted toheat sink 36.

In some embodiments, the heat sink 36 may also be an internal chassisfor supporting other components of laser engine 12. In some embodiments,the light output (power and wavelength) of the edge emitting laser diode14 may be sensitive to temperature and should be held to a predeterminedmaximum temperature rise (e.g., about 25° C.). Thus, the heat sink 36may include a temperature feedback system to automatically disable thelaser if the maximum temperature is exceeded.

The edge emitting laser diode may be powered by one or more batteries20, by way of a momentary switch 210 (activated by power button 200shown in FIG. 4) and pulsing electronics 212, which control the pulsingof the edge emitting laser diode 14. The components shown in FIG. 6 maybe contained in a laser engine housing 24, which may include housingsections held together by any suitable fasteners. As discussed above,other light sources, e.g., an laser diode bar or VCSEL (or multiple edgeemitting laser diodes, laser diode bars or VCSELs), may be used insteadof a single edge emitting laser diode. Furthermore, other power supplysources 20 may be used, such as a rechargeable battery (e.g., L-ionbattery), mains electricity, or a super-capacitor, for example.

FIGS. 5A and 5B also show an example configuration of the applicationend 42 of the laser engine assembly 12, which may include a window 44covering an aperture 220 through which the laser beam 60 is deliveredfrom the edge emitting laser diode 14 to the skin. In this embodiment,window 44 comprises a transparent layer or pane (e.g., sapphire, glass,or plastic) positioned over aperture 220 to protect the internalcomponents of laser engine 12. In other embodiments, aperture 220 may beopen or laser engine 12 may be protected by a transparent (to edgeemitting laser diode 14) encapsulant, such as suitable epoxy orspun-on-glass, rather than window 44. Aperture 220 may have any suitablesize and shape. Laser engine assembly 12 may act as application end 42of device 10, and thus contact the skin directly. Application end 42 mayalso form part of one or more of the sensors 26, such as providing acapacitive antenna for a skin contact sensor. Window 44 may projectbeyond an outer surface 218 of application end 42, may be arranged flushwith outer surface 218 of application end 42, or may be recessed fromouter surface 218 of application end 42.

In some embodiments, device 10 shown in FIGS. 4-7 is configured as adirect exposure, close proximity device, as such terms are definedherein. As discussed above, a non-optically-powered transparent layer orpane, or encapsulant, may be positioned between the edge emitting laserdiode 14 and the target surface, or there may be nothing but an air gapbetween the edge emitting laser diode 14 and the target surface.

In some embodiments, the emitting surface of edge emitting laser diode14 is configured to be located within 5 mm of the target skin surface.In certain embodiments, the emitting surface 82 of edge emitting laserdiode 14 is configured to be located within 2 mm of the target skinsurface, to provide a desired beam spot size and intensity at the targetsurface. In some embodiments, the emitting surface 82 of edge emittinglaser diode 14 is configured to be located within 1 mm of the targetskin surface, to provide a desired beam spot size and intensity at thetarget surface. In particular embodiments, the emitting surface 82 ofedge emitting laser diode 14 is configured to be located within 500 μm,200 μm, or even 100 μm of the target skin surface during use. Due to thevery small distance between the edge emitting laser diode 14 and thetarget skin surface, as well as lack of optics, the edge emitting laserdiode 14 need not be aligned with high precision.

In some embodiments, various aspects of device 10 (e.g., the type ofedge emitting laser diode 14, the distance between edge emitting laserdiode 14 and the skin surface, etc.) are configured to produce treatmentspots 62 on the skin having a diameter of less than 2,000 μm in thelargest dimension. In particular embodiments, the beam spot size on thetarget surface has a diameter of less than 700 μm in the largestdimension, which may be suitable for certain treatments, e.g., treatmentof solar lentigo (age spots), wrinkles, and/or fine lines. In specificembodiments, the beam spot size on the target surface has a diameter ofbetween about 75 μm and about 350 μm in the largest dimension, which maybe suitable for certain treatments, e.g., treatment of wrinkle and/orfine lines. The diameters listed above do not account for any “blurring”or “smearing” of the treatment spots 62 caused by movement of device 10across the skin during the particular beam pulse. The actual diameter ofparticular treatment spots 62 (in the direction of device 10 movementacross the skin) may thus be larger than the nominal diameters listedherein, due to such blurring or smearing of spots 62.

In some embodiments, device 10 is configured to produce treatment spots62 having an area of less than 1.0 mm². In particular embodiments,device 10 is configured to produce treatment spots 62 having an area ofless than 0.4 mm², which may be suitable for certain treatments, e.g.,treatment of solar lentigo (age spots), wrinkles, and/or fine lines. Inspecific embodiments, device 10 is configured to produce treatment spots62 having an area of less than 0.1 mm², which may be suitable forcertain treatments, e.g., treatment of wrinkle and/or fine lines orpigmentation. Finally, in some embodiments, device 10 is configured toproduce treatment spots 62 having an area of less than 0.05 mm², whichmay also be suitable for certain fractional treatments. The treatmentsize areas listed above do not account for any “blurring” or “smearing”of the treatment spots 62 caused by movement of device 10 across theskin during the particular beam pulse. Thus, the actual area ofindividual treatment spots 62 may be larger than the areas listed above,due to such blurring or smearing of spots 62.

In one example embodiment, device 10 is configured such that theemitting surface of edge emitting laser diode 14 is less than 1 mm fromthe target skin surface, and edge emitting laser diode 14 has a nominallaser emitter area of about 100 μm (in the slow axis direction) by 5 μm(in the fast axis direction). This configuration may yield treatmentspots 62 having an equivalent nominal diameter of between about 150 μmand about 350 μm.

FIG. 7 illustrates portions of an example electrical schematic of thelaser pulsing electronics 212 for controlling the pulsing the edgeemitting laser diode 14 of the example embodiment shown in FIGS. 4-6,according to one embodiment. In this embodiment, the laser pulsingelectronics 212 generate current pulses through the edge emitting laserdiode 14 at a fixed rate as long as the signals from the appropriatesensor(s) 26 are valid and the manual power button 200 is activated. Thepulse energy may be controlled via the pulse duration. A single-cellAA-sized Li battery may be used to provide a drive current of about 7Amps through the edge emitting laser diode, to provide a laser outputpower of about 3 Watts, sufficient to produce a desired tissue responsefor particular applications or treatments, e.g., certain fractionaltreatments.

As discussed above, the pulse rate may be set or selected based on atypical or expected manual glide speed of device 10 is across the skin.In particular, the pulse rate may be set or selected such that for arange of typical or expected manual glide speeds (e.g., between 2 cm/sand 6 cm/s), adjacent treatment spots 62 are physically separated fromeach other by areas of non-treated skin, i.e., fractional treatment isprovided. In some embodiments, the pulse rate may be set or selectedsuch that for a range of typical or expected manual glide speeds (e.g.,between 2 cm/s and 6 cm/s), adjacent treatment spots 62 are physicallyseparated from each other from a predetermined minimum non-zerodistance, e.g., 500 μm.

In some embodiments, device 10 may provide a pulse repetition frequency(“PRF”) between 1 and 50 Hz. For example, device 10 may provide a PRF ofbetween 5 and 25 Hz. In particular embodiments, device 10 may provide aPRF of about 15 Hz.

In some embodiments, device 10 may be controlled to prevent, limit, orreduce the incidence or likelihood of treatment spot overlap, e.g.,based on feedback from one or more sensors 26 (e.g., a displacementsensor 100, speed/motion sensor 102, and/or a dwell sensor 116). In someembodiments, the pulse rate may be automatically adjustable by device 10and/or, manually adjustable by the user, e.g., to accommodate differentmanual movement speeds and/or different comfort levels or pain tolerancelevels of the user.

FIG. 8A illustrates an example of a manually scanned pattern oftreatment spots 62 generated in a treatment area of skin 40 by anembodiment of device 10 including a single beam source configured toemit a single pulsed beam 60, e.g., a single edge emitting laser diodeor a single VCSEL configured to emit a single beam 60. Device 10 isglided across the skin while the single beam source is pulsed to createa pattern of spaced-apart treatment spots 62. Each glide of the devicein a particular direction creates a generally linear array of treatmentspots 62. A first array produced by a first glide, or “manual scan,” ofdevice 10 across the skin is indicated at 92. five linear arrays ofspots 62 corresponding to five manual scans 92 of device 10 are shown inFIG. 8A. Device 10 may be manually scanned across the skin any number oftimes and in any direction or directions to effectively cover aparticular treatment area 40. The treatment spot pattern may thereforebe random or quasi-random, unlike certain mechanically scanned systems,which may have benefit, such as to be less cosmetically detectable tothe eye than a more regular grid.

FIG. 8B illustrates an example of a manually scanned pattern oftreatment spots 62 generated in a treatment area of skin 40 by anembodiment of device 10 including multiple beam sources configured toemit multiple discrete pulsed beams 60, e.g., multiple edge emittinglaser diodes, an laser diode bar, multiple laser diode bars, multipleVCSELs, or a VCSEL configured to emit multiple discrete beams 60 (e.g.,as discussed below with reference to FIGS. 30-34), for example. Device10 is glided across the skin while the multiple beam sources of device10 are pulsed (simultaneously, sequentially among the individual beamsources, randomly, or otherwise, depending on the particular type ofbeam sources and configuration of device 10) to create a pattern ofspaced-apart treatment spots 62. Each pulse of the multiple beam sourcesgenerates a corresponding array of multiple treatment spots 62,indicated at 94 in FIG. 8B (in this example, 6 spots, such as might begenerated by a laser diode bar with 6 spaced emitters). Thus, eachmanual glide of the device in a particular direction creates a generallytwo-dimensional array of treatment spots 62. Two manual glides, or“manual scans,” of device 10 across the skin are indicated at 92A and92B. Device 10 may be manually scanned across the skin any number oftimes and in any direction or directions to effectively cover aparticular treatment area 40. In this example, treatment spots areelongated in the glide direction, which could occur from “smearing” ifcompensation is not included, or from the beam properties itself havinga non-symmetric energy profile.

FIGS. 8C-8J illustrate example manual glide, or “manual scan,” patternsfor covering a particular treatment area 40 using device 10. FIGS. 8C-8Gillustrate example patterns in which device 10 is manually scanned inthe same general direction (e.g., back and forth along parallel ornear-parallel directions). In some treatments or applications, device 10may be scanned in two or more different directions, e.g., to form acriss-cross pattern, such as shown in FIG. 8H, for example. This mayyield a more uniform coverage pattern. Other example manual scanpatterns include a generally spiral pattern, as shown in FIG. 81, or arandom pattern, as shown in FIG. 8J. Certain treatment patterns may bepreferred or specified or configured, such as a series ofone-dimensional treatment lines that radiate outward from the eyebrow toachieve a skin tightening effect analogous to a surgical eyebrow lift),for any suitable benefit. Areas may also be treated in multiple passes,e.g., to increase treatment spot density, increase randomness, or otherreason. Any other suitable manual scan patterns may be used asappropriate.

FIG. 9 shows a three-dimensional cross-section of a volume of skin forillustrating the process of a non-ablative fractional treatmentconsisting of an array of MTZs in the skin 64. Each MTZ 64 is a smallvolume of denatured (or otherwise influenced, such as photochemical orphotobiological) epidermis and dermis generally shaped as a column orelongated bowl and extending downward from the skin surface orsubsurface in a direction substantially orthogonal to the skin surface.The damaged skin of the MTZ 64 is surrounded by untreated (and thus notdenatured, in this example) skin. Because of the proximity of healthyskin cells, the damaged skin of the MTZ 64 heals relatively quickly (ascompared to traditional non-fractional treatments, such as CO2 laserresurfacing) and reduces wrinkles, scarring, and/or uneven pigmentationas part of the healing process. During the healing process, MENDS(microscopic epidermal necrotic debris) may be formed. Since the MTZstypically cover only a fraction (e.g., less than 1% to about 70% of theskin surface, side effects may be substantially reduced as compared totraditional non-fractional treatments, such as CO2 laser resurfacing. Insome home-use embodiments of this disclosure, coverage fraction may bebetween 0.25% and 5% of the skin per treatment. In some embodiments,device 10 is configured such that the size and shape (e.g., height andwidth and depth) of the MTZs 64 spare many of the stem cells andmelanocytes in the papillary dermis.

Prevention of Treatment Spot Overlap

As discussed above, in some embodiments, device 10 may be configured toprevent, limit, or reduce the incidence or likelihood of treatment spotoverlap, e.g., based on feedback from one or more sensors 26 (e.g., adisplacement sensor 100, speed/motion sensor 102, and/or a dwell sensor116). For example, in some embodiments, the pulse rate may beautomatically adjustable by device 10 and/or manually adjustable by theuser, e.g., to accommodate different manual movement speeds and/ordifferent comfort levels or pain tolerance levels of the user.

Some embodiments include other devices or techniques that individuallyor in combination provide over-treatment protection, e.g., to preventpulse stacking, firing on the same area, an excessive treatment spot 62density, or other non-desirable treatment conditions. For example, insome embodiments, device 10 ceases to operate (e.g., generate or deliverbeams) when stationary condition of device 10 is detected. A stationarycondition may be determined using one or more sensors, e.g., any one ormore motion sensors, speed sensors, dwell sensors, vibration and tiltsensors, accelerometers, and/or displacement sensors. Such sensors maygenerate signals based on capacitance, optical reflection, remittance,scattering variation, acoustical reflection variation, acousticalimpedance, galvanic potential, potential difference, dielectric constantvariation, or any other parameter.

In some embodiments, device 10 uses local pyrometry (alone or incombination with other techniques mentioned above) to detect astationary condition. The treatment beam area may be optically measuredby local thermal imaging of the skin, and a stationary condition may bedetected where local heating of the skin exceeds a threshold temperatureor other parameter value.

In some embodiments, device 10 fires an “encouragement pulse” when astationary condition is detected. For example, a single non-damaging buthigher than normal energy pulse (causing discomfort but not damage) or abrief pulse train may be emitted if a stationary condition is detected,to encourage the user to move device 10.

A stationary condition may further be measured by bulk heatingmeasurement, for example. If the tip of the treatment delivery device orthe sensed skin temperature or region of skin temperature begins to heatabove a threshold, loss of motion is detected, or excessive treatment inthe area is detected.

As another example, device 10 may deliver heat or cold to the skin toencourage motion, as dwelling in one location may become uncomfortable.As another example, mechanical rollers may be used to detect anon-motion condition. Alternatively, motorized rollers may drive motionof device 10 across the skin, thus physically avoiding a non-motioncondition.

In some embodiments, physiological feedback based on beamcharacteristics may be exploited, e.g., by designing the output fortreatment efficacy as well as perception of the presence of treatment.For example, discomfort may be exploited such that overtreatment isdiscouraged by pain feedback that increases with excessive treatment.

In some embodiments, photobleaching may be used with indigenous orexogenous substances. For example, the skin may be treated with a dyethat is photobleached by the treatment beam or by a separate bleachingbeam used to bleach the treated area and potentially its surroundingareas. In this example, device 10 may be configured to detect thepresence of the unbleached dye and would allow treatment only on areaswith unbleached dye, thus preventing repetitive treatment on the samearea (since that would be photobleached).

Any of the over-treatment protection systems or techniques describedabove (expect those directly concerned with pulse parameters) may besimilarly incorporated in any CW radiation embodiment, e.g., for a hairremoval device.

Pulse Rate Frequency (PRF)

In embodiments that include a pulsed radiation source 14 (e.g., with oneor more pulsed beam sources), the pulse rate frequency (PRF) may befunctionally interrelated with one or more other configurational oroperational parameters of device 10, including (a) the manual glidespeed, (b) spacing between treatment spots generated by consecutivepulses, referred to herein as “consecutive spot spacing,” and (c) theamount of “smearing” or “blurring” of individual treatment spots. Theamount of “smearing” or “blurring” of a treatment spot may be quantifiedby a “blur factor,” defined as the ratio of the area of the blurredtreatment spot 62 (with blurring caused by movement of device 10) to thearea of the instantaneous treatment spot size. Thus, to illustrate, ablur factor of 1.0 indicates no blurring, a blur factor of 2.0 indicatesa doubling of the treatment spot size area, and a blur factor of 3.0indicates a tripling of the treatment spot size area.

Further, in at least some embodiments, the consecutive spot spacing andthe blur factor for any particular operation of device 10 are defined asa function of (a) the manual glide speed, (b) the instantaneous spotsize (i.e., the spot size at any particular instant, thus ignoring anyburring affects), and (c) any set of parameters that defines the timingof a pulse sequence (referred to herein as “pulse timing parameters,”e.g., selected from pulse duration (i.e., pulse on-time), delay betweenpulses (i.e., pulse off-time), pulse rate frequency (PRF), duty cycle,etc.

In some embodiments, the pulse rate frequency (PRF) and/or one or moreother pulse timing parameters are controlled to provide (a) a predefinedor selected minimum consecutive spot spacing, and/or (b) a predefined orselected maximum amount of spot blurring (e.g., a predefined or selectedmaximum blur factor), and/or (c) any other target parameter(s).“Controlling” the PRF and/or pulse timing parameter(s) may include:

(a) device 10 selecting or setting the PRF and/or at least one otherpulse timing parameter, e.g.:

-   -   (i) automatically selecting a PRF and/or at least one other        pulse timing parameter based on a user-selected operational        mode, treatment level, or other user input, or    -   (ii) automatically selecting a PRF and/or at least one other        pulse timing parameter independent of user input (e.g., based on        a device-selected operational mode, treatment level, or other        level, or based on a detected glide speed during a portion of a        treatment or a pre-treatment period of operation (e.g., using a        motion/speed sensor 102), based on a glide speed detected and        stored from a previously performed treatment (e.g., using a        motion/speed sensor 102), based on one or more parameters        detected by sensor(s) 26 in real time or otherwise (e.g., as        skin temperature detected by temperature sensor(s) 106, or skin        color detected by pigment sensor(s) 110, for example), or based        on any other any other data or signals collected in real time or        otherwise; and/or

(b) device 10 dynamically adjusting the PRF and/or at least one otherpulse timing parameter during a treatment session (e.g., in real time orsubstantially in real time), e.g., (i) based on feedback from one ormore sensors 26, e.g., device displacement detected by displacementsensor(s) 100, glide speed detected by motion/speed sensor(s) 102, skincontact sensor(s) 104, skin temperature detected by temperaturesensor(s) 106, delivered radiation detected by radiation sensor(s) 108,skin color detected by pigment sensor(s) 110, signals from eye safetysensor(s) 114, dwell status detected by dwell sensor(s) 116, and/ordevice displacement and/or glide speed detected by roller-basedsensor(s) 118, and/or (ii) based on based on any other any other data orsignals collected in real time or otherwise.

As discussed above, in some embodiments, the PRF and/or at least oneother pulse timing parameter are controlled to provide (a) a predefinedor selected minimum consecutive spot spacing and/or (b) a predefined orselected maximum amount of spot blurring (e.g., a predefined or selectedmaximum blur factor).

For example, in some embodiments, the PRF and/or at least one otherpulse timing parameter are controlled to provide a minimum consecutivespot spacing of 1 mm. Assuming a glide speed of between 2 cm/s and 6cm/s, and a spot size of between 200 μm and 600 μm, a PRF of 15 Hz,pulse duration of 3 ms, and duty cycle of 4.5% may be selected toprovide such spot spacing. At these operational parameters, theresulting blur factor is about 130 to 190% for a spot size of 200 μm,and about 110 to 130% for a spot size of 600 μm.

As another example, in some embodiments, the PRF and/or at least oneother pulse timing parameter are controlled to provide a minimumconsecutive spot spacing of 0.5 mm. Assuming a glide speed of between 2cm/s and 6 cm/s, and a spot size of between 300 μm and 600 μm, a PRF of30 Hz, pulse duration of 5 ms, and duty cycle of 15% may be selected toprovide such spot spacing. At these operational parameters, theresulting blur factor is about 133 to 200% for a spot size of 300 μm,and about 117 to 150% for a spot size of 600 μm.

In some embodiments, a PRF of between 1 and 50 Hz is selected. Forexample, device 10 may provide a PRF of between 5 and 25 Hz. Inparticular embodiments, device 10 may provide a PRF of about 15 Hz.

In some embodiments, the device 10 is controlled to provide a minimumconsecutive spot spacing of 1 mm. For example, the device 10 maycontrolled to provide a minimum consecutive spot spacing of 0.5 mm. Inparticular embodiments, the device 10 may controlled to provide aminimum consecutive spot spacing of 0.25

In some embodiments, a pulse duration of between 1 ms and 10 ms may beselected. In certain embodiments, a pulse duration of between 2 ms and 8ms [smaller range] may be selected. In particular embodiments, a pulseduration of between 3 ms and 6 ms may be selected.

Some Example Embodiments and Example Operation Parameters

Any of the various features and configurations discussed herein may becombined in any suitable manner, for providing a variety of differenttreatments. Some example configurations with example parameter valuesare provided below. It should be understood that these are examplesonly.

Table 1 below shows example values and parameters for one exampleembodiment of device 10 similar to the device shown in FIGS. 4-7. Inthis example, to achieve 250 treatment spots/cm² and a fractionalcoverage ratio of 2.5% with 8 mJ/treatment spot, and the stated minimumcoverage rate and duty factor, a 1.73 W light source is pulsed at 30 Hzand the application end or “tip” moved with a speed of 3.43 cm/s. Thecalculated blur factor caused by the movement of the treatment tip 42across the skin and other parameters are also indicated.

TABLE 1 Pameter Example Target Value MTZ per cm2 250 treated skin (%)2.5 area treated per MTZ (sq microns) 10000 spot dia, no motion(microns) 113 energy per mtz (mJ) 8 fluence, no motion (J/cm2) 80 mincov rate (cm2/min) 13 min cov rate (cm2/s) 0.22 min prf (hz) 30 maxperiod (s) 0.0185 duty factor (%) 25 on time (s) 0.0046 tip speed (cm/s)3.43 actual area treated (microns) 27841 blur factor 2.8 actual fluence(J/cm2) 29 power (w) 1.73

Table 2 below shows example parameters and values for another exampleembodiment of device 10 similar to the device shown in FIGS. 4-7. Adevice with substantially these parameters has been clinically tested onhuman subjects and animal models and shown to produce desirable tissueresponse and clinical benefit, such as texture improvement and reductionin pigmented lesions.

TABLE 2 Parameter Example Value Mechanical Size (Length × Diameter)about 12 cm × about 1.7 cm (4.7 in. × 0.7 in.) Weight 46 gr. Electrical:Battery (AA) LiFePO4 Batterty Life between recharges about 2 hrs DriveCurrent 7.6 A Laser Diode Voltage 2.1 V Optical: Pulse Energy 14 mJPulse Repetition Rate 10 Hz Pulse Width 3.3 ms Peak Power 4.24 W AveragePower 0.14 W Wavelength 1450 nm E/O efficiency 26.6%

Table 3 below shows example values and parameters for three exampleconfigurations of an example device 10 similar to the device shown inFIGS. 4-7. The table shows, for each of the three exampleconfigurations, different optical power, pulse-on and pulse-off times,treatment spot diameters, treatment tip dimensions, and scan speeds.Resulting pulse rates, energy per pulse, minimum scan speed for fullcoverage, illuminated area, blur effect, fluency, and other parametersare also shown. Also shown are calculations related to over-treatmentprotection where, in this particular example, photobleaching is used todifferentiate treated and untreated areas. The treatment spot sizes andenergies can be obtained by direct-coupled edge emitting laser diodeemission (e.g., from one or more single-beam edge emitting laser diodein close proximity to the skin with no intervening optics 16 (although aprotective window may be provided) or by a fiber delivered beam or byother suitable optical means. For example, an edge emitting laser diodebeam source of 500 micron chip size and 100 micron beam source size maybe used to obtain the parameters shown if placed in very close proximityto the skin.

TABLE 3 Example Example Example Parameter Config. 1 Config. 2 Config. 3optical power (W) 4 7 7 on time of pulse (ms) 10 10 8 off-time of pulse(ms) 30 30 8 PRF (hz) 25 25 63 energy per pulse (mJ) 40 70 56 spotdiameter (microns) 150 220 150 square tip dimension (microns) 625 625625 min scan speed for full coverage 1.56 1.56 3.91 (cm/s) scan speed(cm/s) 0.50 2.00 3.91 illuminated area per MTZ (mm2) 0.0252 0.08200.0646 blur (illum area/spot size) 1.4 2.2 3.7 Fluence per MTZ (J/cm2)159 85 87 area treated per second (mmw2) 0.63 2.05 4.04 area bleachedper pulse (sq mm) 0.39 0.39 0.39 area bleached per second (mm2) 9.779.77 24.41 (area treated)/(area bleached) 6% 21% 17% area bleached perminute (cm2) 5.86 5.86 14.65 area bleached per minute (in2) 0.91 0.912.27

Table 4 below shows example parameter values for a direct exposureembodiment using a low fill-factor laser diode bar as the radiationsource 14B, operating in a gliding mode in which the device is glidedperpendicular to the elongated direction of the laser diode bar 14B,with pulsed radiation for fractional treatment. Each pulse of the laserdiode bar 14B generates a linear array of discrete, spaced-aparttreatment spots 62, each corresponding to one emitter 80 of the laserdiode bar 14B, e.g., as discussed with respect to FIGS. 22A and 22B.

TABLE 4 Parameter Example value Specific example Radiation source =laser diode bar Total optical efficiency (laser diode 70%-90% about 80%bar to target) Proximity gap spacing 1 mm-10 mm about 1.5-2.5 mm Poweremitted per emitter 1.3-9 W 2.4 W total emitted by diode bar 50-80 W 70W Pulse characteristics pulse on-time 2-20 ms 6 ms duty cycle 10-60% 50%Length of instantaneous irradiated 0.1-0.6 mm 0.2 mm area on target fromsingle beam source (perpendicular to elongated direction of diode bar)Width of instantaneous irradiated 0.1-0.6 mm 0.3 mm area on target fromsingle beam source (parallel to elongated direction of diode bar) Manualglide speed 2-6 cm/s 4 cm/s Total width of treatment spot 62 0.5-2 cm 1cm pattern (parallel to elongated direction of diode bar) Length ofindividual treatment spot 0.1-1 mm 0.3 mm 62 (perpendicular to elongateddirection of diode bar) Area of individual treatment spot 0.04-0.6 mm²0.09 mm² Width of non-irradiated areas 150-800 μm 300 μm betweenindividual treatment spots 62 (parallel to elongated direction of diodebar) Energy delivered per individual 2-100 mJ 12 mJ treatment spotLength of non-irradiated areas 0.1-1.2 mm 0.25 mm between successivetreatment spot 62 patterns (perpendicular to elongated direction ofdiode bar)

Single-Beam Edge Emitting Laser Diodes

As discussed above, in some embodiments, radiation source 14 is an edgeemitting laser diode (or multiple edge emitting laser diodes) includinga single emitter (i.e., a single beam source) that generates a singlelaser beam. In a typical edge emitting laser diode, the emitted beam hasa beam divergence of nearly 45° in the fast axis direction and about 10°in the slow axis.

Due to the rapid divergence in the fast axis direction, the laser diodebar provides a significant beam spread in this fast axis direction, inthe absence of optical elements provided downstream of the laser diodebar. Therefore, in order to capture a desired portion of the beam energy(and/or maintain a desired beam intensity), certain embodiments areconfigured as “close proximity” devices in which the “proximity gapspacing” is less than or equal to 10 mm. As used herein, the “proximitygap spacing” or “PGS” is defined as the distance between the emittingsurface of the radiation source (in this case, the edge emitting laserdiode) and the skin-contacting surface of device 10, i.e., the distancebetween the emitting surface of the radiation source and the skin duringa treatment position of device 10 on the skin.

In some embodiments, the proximity gap spacing is less than or equal to5 mm, 2 mm, or even 1 mm. In particular embodiments, the proximity gapspacing is less than 500 μm, less than 200 μm, or even less than 100 μm.The proximity gap spacing may be selected based on one or moreparameters, e.g., the desired size and/or intensity of treatment spots62 delivered to the skin, and/or manufacturing constraints or costs.

FIGS. 10-14 illustrate example direct exposure configurations, which mayfurther be configured for “close proximity” radiation, depending on theproximity gap spacing or “PGS” of the particular embodiment. Thus, incertain embodiments, device 10 configured as shown in any of FIGS. 10-14may have a proximity gap spacing of less than or equal to 10 mm, 5 mm, 2mm, 1 mm, 500 μm, 200 μm, or even 100 μm in particular configurations.

FIG. 10 illustrates a simplified cross-sectional side view of an exampleembodiment of device 10 that includes an edge emitting laser diode 14Aincluding an emitter 80 having an emitting surface 82. A transmissivewindow 44 (e.g., a sapphire or other transmissive window, or a thintransmissive film) is located at the application end 42 of device 10,and forms a skin-contacting surface 74 with the skin 40. In someembodiments, manufacturing or other limits may prevent the emitter 80from being placed directly onto the window 44, thus forming a gapbetween emitter 80 and window 44. Thus, the proximity gap spacing (PGS)between the emitting surface 82 of edge emitting laser diode 14Aincludes the thickness of the window 44 (T_(W)) plus the gap distance(D_(G)) between the emitting surface 82 and the window 44. In otherembodiments, emitter 80 or emitting surface 82 may be placed directlyonto the window 44, such that the gap distance (D_(G)) is effectivelyzero.

In some embodiments, window 44 has a thickness (T_(W)) of between about100 μm and about 200 μm, with a gap distance (D_(G)) of about 50-150 μm,providing in a proximity gap spacing (PGS) of between about 150 μm andabout 350 μm. In other embodiments, window 44 is a thin film having athickness of less than 150 μm, e.g., about 75 μm, such that theproximity gap spacing (PGS) may be about 125-225 μm, depending on thegap distance (D_(G)).

In one example embodiment, window 44 is a sapphire window with athickness of about 140 μm, with a gap distance of about 100 μm,providing a proximity gap spacing (PGS) of about 240 μm. At a proximitygap spacing of 240 μm, an edge emitting laser diode that emits a1-micron by 95-micron beam with divergence of 28 deg FWHM (fast axis) by6 deg FWHM (slow axis), respectively, will form an approximatelycircular treatment spot on the skin having a diameter of about 120 μm.With a device glide speed of about 2 cm/s and a 5 ms pulse duration, thetreatment spot becomes an oval of about 120 μm by 220 μm in respectivediameters. In another example embodiment, window 44 is a sapphire windowwith a thickness of about 180 μm.

FIG. 11 illustrates an example configuration in which the window 44 isset back from the skin by an offset distance (D_(O)), with another partof the treatment tip forming the skin-contacting surface 74. Such offsetmay be provided for any suitable reason, e.g., to protect the windowfrom damage, to keep the window clean, or to avoid friction between thewindow and the skin. The proximity gap spacing (PGS) in thisconfiguration is composed of the thickness of the window 44 (T_(W)), thegap distance (D_(G)) between the emitting surface 82 and the window 44,and the offset distance (D_(O)) of the window 44.

FIG. 12 illustrates an example configuration that excludes a window,such that the emitter 80 is exposed to open air. Thus, the proximity gapspacing (PGS) may be set at any desired distance, or even zero (i.e.,with the emitting surface 82 touching the skin). However, the edgeemitting laser diode 14A may be set back from the skin-contactingsurface 74 by some distance, e.g., to protect the edge emitting laserdiode from damage, to keep the edge emitting laser diode clean, to avoidfriction between the edge emitting laser diode and the skin, or toprovide some distance for the beam to diverge (in particular, in thefast axis direction) by a suitable amount to form a suitable treatmentspot size on the skin or eye safety or other benefits.

FIG. 13 illustrates an example configuration that excludes a window, butincludes a film or other coating over the leading surface of edgeemitting laser diode 14A, e.g., to protect the edge emitting laser diodefrom damage, provide electrical isolation, or for other purposes. Theproximity gap spacing (PGS) may be set at any desired distance (limitedonly by the film thickness), or even such that the film-covered emittingsurface 82 touches the skin. However, as discussed above regarding FIG.12, the edge emitting laser diode 14A may be set back from theskin-contacting surface 74 by some distance, e.g., to protect the edgeemitting laser diode from damage, to keep the edge emitting laser diodeclean, to avoid friction between the edge emitting laser diode and theskin, or to provide some distance for the beam to diverge (inparticular, in the fast axis direction) by a suitable amount to form asuitable treatment spot size on the skin.

FIG. 14 illustrates an example configuration of device 10 similar to theconfiguration of FIG. 10 but including two edge emitting laser diodes14A, each generating a discrete beam 60. Device 10 may include any othernumber of edge emitting laser diodes 14A, arranged in any suitablemanner, e.g., in a row, a two-dimensional array, or any other manner.Each edge emitting laser diode 14A in device 10 may be arranged with theproximity gap spacing between the respective emitter surface 82 and theskin-contacting surface 74, or different edge emitting laser diodes 14Amay be arranged to have different proximity gap spacing (PGS), e.g., toprovide multiple different treatment spot sizes, shapes, or energyintensities at the skin. Two or more edge emitting laser diodes 14A maysimilarly be arranged in any of the configurations shown in FIGS. 10-13,as well as FIGS. 15-16 discussed below. Any of these configurations maysimilarly utilize laser diode bars or VCSELs with single beam ormultiple beams, as discussed below.

FIGS. 15-16 illustrate example indirect exposure configurations (i.e.,including optics between the laser and the skin), which may also beconfigured for “close proximity” radiation, depending on the proximitygap spacing or “PGS” of the particular embodiment. Thus, in certainembodiments, device 10 configured as shown in FIG. 15 or 16 may have aproximity gap spacing of less than or equal to 10 mm, 5 mm, 2 mm, 1 mm,500 μm, 200 μm, or even 100 μm in particular configurations.

FIG. 15 illustrates an example configuration of device 10 including aconcave lens 78 positioned between edge emitting laser diode emitter 80and the skin. Convex lens 78 may act to increase the divergence of thebeam 60 in one or more axis (e.g., fast axis and/or slow axis), e.g., toprovide a desired spot size or shape, and/or to provide increased eyesafety. The lens 78 may be set back from the skin-contacting surface 74,as shown in FIG. 15, or may alternatively be arranged to contact theskin directly. Alternatively, a convex lens could be used to decreasethe divergence of the beam 60 in one or more axis (e.g., fast axisand/or slow axis), e.g., to provide a desired spot size or shape.

FIG. 16 illustrates an example configuration similar to FIG. 15, butincluding a cylindrical lens or a ball lens 79 instead of convex lens78. Cylindrical or ball lens 79 may act to increase the divergence ofthe beam 60 in one or more axis (e.g., fast axis and/or slow axis),e.g., to provide a desired spot size or shape, and/or to provideincreased eye safety. Like lens 78 discussed above, lens 79 may be setback from the skin-contacting surface 74, or may alternatively bearranged to contact the skin directly, as shown in FIG. 16.

In other embodiments, any other type of lens (e.g., aspheric) or otheroptic may be provided to affect the beam 60 as desired.

FIGS. 17A-17C illustrate the asymmetrical divergence of a beam 60emitted from an edge emitting laser diode, in embodiments in which theproximity gap spacing is extremely small. A typical edge emitting laserdiode includes an elongated rectangular emitter 80 having a long sideand a short side. For example, an edge emitting laser diode emitter 80may be about 1 μm by 100 μm, or about 5 μm by 95 μm.

FIG. 17A illustrates a long-side view of an edge emitting laser diodeemitter 80, and illustrates the relatively slow divergence of the beam60 in the slow axis. FIG. 17B illustrates a short-side view of edgeemitting laser diode emitter 80 (perpendicular to the long-side view),and illustrates the relatively fast divergence of the beam 60 in thefast axis. FIG. 17C illustrates a top-down view showing edge emittinglaser diode emitter 80 and a corresponding treatment spot 62 formed byedge emitting laser diode emitter 80, indicating the divergence of thebeam 60 in both the fast axis and slow axis to form a treatment spot 62having a generally oval or rounded-rectangular shape, which is elongatedin the slow-axis direction. A treatment spot 62 elongated in theslow-axis direction, such as shown in FIG. 17C, may be produced by usingan extremely small proximity gap spacing (e.g., less than the slow-axiswidth of the laser diode emitter surface or facet, e.g., about 100 μm).FIG. 17C does not account for any “smearing” or “blurring” of thetreatment spot 62 due to the movement of device 10 due to movement ofdevice 10.

FIGS. 18A-18C are similar to FIGS. 17A-17C, but correspond toconfigurations with a larger proximity gap spacing (e.g., about 500 μmfor an emitter surface or facet having a slow-axis width of about 100μm), whereby the longer propagation of the divergent beam 60 to the skinsurface allows the fast axis divergence to overcome the slow axisdivergence. Thus, the resulting treatment spot 62 may be elongated inthe fast axis direction, as shown in FIG. 18C. Like FIG. 17C, FIG. 18Cdoes not account for any “smearing” or “blurring” of the treatment spot62 due to the movement of device 10 due to movement of device 10.

FIG. 19A illustrates a treatment spot 62 formed by edge emitting laserdiode emitter 80 emitting a beam pulse while device 10 is glided acrossthe skin in the direction of the arrow, with emitter 80 moving thedashed-line image of emitter 80 to the solid-line image of emitter 80during the pulse. Thus, the illustration shows the “smearing” or“blurring” of the treatment spot 62 due to the movement of device 10during the beam pulse. In this orientation, the device movement maysmear or blur the treatment spot 62 perpendicular to the elongateddirection of the instantaneous spot, by an amount that depends at leastupon the pulse duration and the manual glide speed. The longer the pulseduration or the faster the manual glide speed, the greater theelongation (blurring) of spot 62 in the glide direction. In the exampleshown in shown in FIG. 19A, the amount of blurring produces a generallycircular or rounded-rectangular spot 62.

Like FIG. 19A, FIG. 19B illustrates a treatment spot 62 formed by edgeemitting laser diode emitter 80 emitting a beam pulse while device 10 isglided across the skin in the direction of the arrow, with emitter 80moving the dashed-line image of emitter 80 to the solid-line image ofemitter 80 during the pulse. However, in the example shown in FIG. 19B,the device is moved in the elongated direction of the emitter 80, ratherthan perpendicular to the elongated direction of the emitter 80 as shownin FIG. 19A. Thus, the smearing or blurring of the treatment spot 62caused by the device movement may increase the elongation of theresulting treatment spot 62.

Thus, it should be understood from the discussion above that the exactshape and size of the resulting treatment spot 62 may depend on avariety of factors, including at least (a) the size and shape of theparticular emitter 80, (b) the orientation of the emitter 80 relative tothe manual glide direction, (c) the proximity gap spacing between theemitter surface 82 and the skin, (d) the pulse duration, and (e) themanual glide speed. Any one or more (or all) of parameters (a)-(d) maybe selected or controlled by device 10, and a desired manual glide speedmay be encouraged (e.g., by instructing the user) to provide treatmentspots 62 having a desired shape and size.

FIG. 20 is a plot of a detected wavelength profile of laser radiationreceived at a target surface from an example edge emitting laser diode.In this example, the wavelength profile defines an approximatelyGaussian peak at 1450.4

FIGS. 21A and 21B illustrate example dimensions for a treatment spot 62and corresponding MTZ 64 generated by an edge emitting laser diodeconfigured for direct exposure and/or close proximity radiation, e.g.,according to any of the example configurations of FIGS. 10-16. As shownin FIG. 21, an edge emitting laser diode emitter 80 is positioned abovethe skin 40 with either a window 44 (i.e., not an optic 16), a lens 78(i.e., an optic 16), or nothing (e.g., air only) positioned between theemitting surface 82 and the skin 40. Depending on the particularconfiguration, the proximity gap spacing (PGS) between the emittingsurface 82 of the edge emitting laser diode and the skin-contactingsurface of device 10 is indicated as PGS_(A) (for embodiments in whichwindow 44 or lens 78 directly contacts the skin) or PGS_(B) (forembodiments in which window 44 or lens 78 is set back from the skin bysome distance). Where the proximity gap spacing is indicated as PGS_(A)(i.e., embodiments in which window 44 or lens 78 directly contacts theskin), the PGS is equal to the thickness of the window 44 or lens 78(T_(W)) plus the gap distance (D_(G)) between the emitting surface 82and the window 44 or lens 78. As discussed above, in some embodimentsemitter 80 may be placed directly onto the window 44 or lens 78, suchthat the gap distance (D_(G)) is effectively zero.

FIG. 21A also indicates the treatment spot 62 on the skin surface, aswell as the depth of the MTZ 64 extending below the treatment spot 62,indicated as D_(MTZ).

FIG. 21B illustrates the dimensions of the treatment spot 62 on the skinsurface, with the instantaneous treatment spot 62 _(I) shown in solidline and the “blurred” treatment spot 62 _(B) (due to gliding of device10 across the skin during the delivery of the beam pulse) shown indashed line. The instantaneous treatment spot 62 _(I) is defined by afast axis direction width W_(FA), a slow axis direction width W_(SA)_(—) _(I), and an area A_(I). The blurred treatment spot 62 _(B) isdefined by a fast axis direction width W_(FA), a slow axis directionwidth W_(SA) _(—) _(B), and an area A_(B).

In some embodiments, one or more parameters of device 10 may be selectedor controlled to control or limit the amount of blurring of treatmentsspots 62, e.g., to provide an effective spot size and/or fluence orenergy density at the skin within individual treatments spots 62 (e.g.,to achieve the desired dermatological effect in the skin). For example,in some embodiments, one or more of (a) the pulse duration and (b) thefluence or energy density of the emitted beam 60 may be controlled orlimited based on an assumed manual glide speed (e.g., 2-6 cm/s), ameasured manual glide speed, or a measured displacement of device 10across the skin, for example, to limit the blurring of treatments spots62 to a defined maximum blur factor. As stated above, the blur factormay be defined as the ratio of the area of the blurred treatment spot 62(with blurring caused by movement of device 10) to the area of theinstantaneous treatment spot size. Thus, to illustrate, a blur factor of1.0 indicates no blurring, a blur factor of 2.0 indicates a doubling ofthe treatment spot size area, and a blur factor of 3.0 indicates atripling of the treatment spot size area.

In general, the larger the blur factor, the lower the fluence or energydensity at the skin within the area of the blurred treatment spot. Insome embodiments or device settings, a blur factor of up to about 3.0 isgenerally acceptable for providing effective MTZs for a fractionaltreatment. In other embodiments or device settings, a blur factor of upto about 2.5 or up to about 2.0 is generally acceptable for providingeffective MTZs for a fractional treatment. Thus, in some embodiments,one or more device parameters (e.g., the pulse duration and/or thefluence or energy density of emitted beams 60) may be selectedcontrolled to limit the blur factor to less than about 3.0, 2.5, or 2.0,depending on the selected limit Certain embodiments limit the blurfactor to less than about 1.8 or less than about 1.5. Other embodimentsor device settings may allow a blur factor of up to about 3.5 or 4.0.Other embodiments or device settings may allow even larger blur factors.

In some embodiments, the pulse duration may be limited to a definedvalue (e.g., 5 ms) based on an assumed range of manual glide speeds(e.g., 2-8 cm/s) to limit the blur factor to about 2.0. Further, it hasbeen determined that an MTZ 64 need not be circular or axis-symmetric inshape to be effective, and can be elliptical or elongated to a certainextent, e.g., as caused by a manual glide speed between about 6 cm/s and10 cm/s for certain embodiments.

Table 5 shows relevant parameter values for a variety of exampleembodiments of device 10, with reference to FIGS. 21A and 21B.

TABLE 5 Specific Specific Example Example of Example Example ofParameter Embodiment 1 Embodiment 1 Embodiment 2 Embodiment 2 RadiationSingle beam Single beam Single beam Single beam source edge emittingedge emitting laser diode laser diode laser diode laser diode emittersurface 100 (slow- 100 (slow- 100 (slow- 100 (slow- (μm × μm) axis) × 5(fast- axis) × 5 (fast- axis) × 5 (fast- axis) × 5 (fast- axis) axis)axis) axis) window or window window window window lens? beam 35°-45°fast 45° fast axis 35°-45° fast 45° fast axis divergence at axis, 10°slow axis axis, 10° slow axis skin surface 6°-12° slow 6°-12° slow (fastaxis, slow axis axis axis) T_(W) (μm) 150-250 180  50-150 130 D_(G) (μm)200-500 320  50-150 130 PGS (μm) 350-750 500 100-300 260 W_(FA) (μm)225-625 419  70-255 220 W_(SA)_I (μm) 135-260 187 110-165 145 A_(I)(mm²) 0.03-0.16 0.078 0.01-0.04 0.032 manual glide 2-6 4 1-4 2 speed(cm/s) W_(SA)_B (μm) 155-740 307 (W_(SA)_B; 120-765 225 (W_(SA)_B; glidein slow- glide in slow- axis direction) axis direction) A_(B) (mm²)0.03-0.46 0.129 0.01-0.20 0.050 Pulse duration 1-8 3  1-15 4 (ms) Power(W) 2-6 4 1-4 3 Total energy  5-15 12  5-15 12 per pulse (mJ) Energydensity 1.1-50  9.3  2.5-150 24 (J/cm²) D_(MTZ) (μm) 100-400 260 120-700350 Pulse 10-30 15 10-40 20 frequency rate (Hz) Specific SpecificExample Example of Example Example of Parameter Embodiment 3 Embodiment3 Embodiment 4 Embodiment 4 Radiation Single beam Single beam Singlebeam Single beam source laser diode laser diode laser diode laser diodeemitter surface 100 (slow- 100 (slow- 100 (slow- 100 (slow- (μm × μm)axis) × 5 (fast- axis) × 5 (fast- axis) × 5 (fast- axis) × 5 (fast-axis) axis) axis) axis) window or convex rod convex rod neither (air)neither (air) lens? lens lens beam 2°-8° fast axis, 5° fast axis 35°-45°fast 45° fast axis divergence at 6°-12° slow 10° slow axis axis, 10°slow axis skin surface axis 6°-12° slow (fast axis, slow axis axis)T_(W) (μm)  50-150 130 N/A N/A D_(G) (μm)  400-2500 2000  50-150 100 PGS(μm)  450-3000 2130  50-150 100 W_(FA) (μm)  20-425 191  35-130 88W_(SA)_I (μm) 145-730 473 105-130 117 A_(I) (mm²) 0.003-0.31  0.0900.004-0.02  0.010 manual glide 2-6 4 1-4 2 speed (cm/s) W_(SA)_B (μm) 40-900 351 (W_(FA)_B;  45-450 168 (W_(FA)_B; glide in fast- glide infast- axis direction) axis direction) A_(B) (mm²) 0.006-0.66  0.1660.005-0.06  0.020 Pulse duration 1-8 4 1-8 4 (ms) Power (W) 2-6 3 2-6 3Total energy  5-15 12  5-15 12 per pulse (mJ) Energy density  0.8-2507.2  8-300 60 (J/cm²) D_(MTZ) (μm) 100-700 250 250-700 450 Pulse 10-3015 10-40 30 frequency rate (Hz)

Laser Diode Bars

As discussed above, in some embodiments, radiation source 14 is an laserdiode bar (or multiple laser diode bars) including multiple emitters,each acting as a discrete beam source that generates a discrete laserbeam. In a typical laser diode bar, the beam emitted from each beamsource (emitter) of the laser diode bar has a beam divergence of nearly45° in the fast axis direction and about 10° in the slow axis.

Due to the rapid divergence in the fast axis direction, the laser diodebar provides a significant beam spread in this fast axis direction, inthe absence of optical elements provided downstream of the laser diodebar. Therefore, as with an edge emitting laser diode, in order tocapture a desired portion of the beam energy (and/or maintain a desiredbeam intensity), certain embodiments are configured as close proximitydevices in which the proximity gap spacing (the spacing between emittingsurfaces of the laser diode bar and the skin-contacting surface 74 ofdevice 10) is less than or equal to 10 mm. In certain laser diode barembodiments, device 10 may have a proximity gap spacing of less than orequal to 5 mm, 2 mm, 1 mm, 500 μm, 200 μm, or even 100 μm, depending onthe desired size and/or intensity of the treatment spots 62 generated bythe laser diode bar.

The multiple beams emitted by the multiple emitters of an laser diodebar may (a) remain separate during their propagation to the skin to formmultiple, spaced-apart treatment spots 62 on the surface of the skin, or(b) partially or substantially combine during their propagation to theskin (due to the divergence of the individual beams) to form a singlecontiguous treatment spot 62 with substantially uniform or spatiallymodulated energy profile, depending at least on (a) the proximity gapspacing between the emitting surfaces of the laser diode bar and theskin, (b) the size and shape of each emitter of the laser diode bar, and(c) the fill factor of the laser diode bar.

FIGS. 22A-23B illustrate example embodiments in which the multiple beamsemitted by the multiple emitters of an laser diode bar remain separateand form multiple, spaced-apart treatment spots 62 on the skin. Suchembodiments may be suitable or advantageous for certain applications ortreatments, e.g., certain fractional treatments. In contrast, FIGS.24A-24B illustrate an example embodiment in which the multiple beamsemitted by the multiple emitters of an laser diode bar combine duringtheir propagation to the skin (due to the divergence of the individualbeams) to form a single contiguous treatment spot 62. In particular, theexample embodiment of FIGS. 24A-24B includes a “high fill-factor” laserdiode bar that promotes the combination of the individual beams to forma single contiguous treatment spot 62 on the skin. Such embodiments maybe suitable or advantageous for certain applications or treatments,e.g., hair removal treatments, bulk heating for skin tightening, oracne, for example, or non-ablative wrinkle treatments.

Turning first to FIGS. 22A-23B, FIG. 22A illustrates a simplifiedcross-sectional side view of an embodiment similar to the embodiment ofFIG. 10, but including an laser diode bar 14B instead of asingle-emitter edge emitting laser diode 14A as the radiation source.Laser diode bar 14B includes multiple emitters 80 arranged in a row,with each emitter 80 acting as a discrete beam source that generates adiscrete laser beam 60. The multiple beams 60 emitted by the multipleemitters 80 of the laser diode bar 14B form a linear array ofspaced-apart treatment spots 62 on the skin, and thus a correspondinglinear array of spaced-apart MTZs 64 in the skin. This embodiments maybe suitable for fractional treatment, for example. Laser diode bar 14Bmay include any suitable number of emitters 80.

Laser diode bar 14B may be controlled to deliver pulsed radiation,continuous wave (CW) radiation, or otherwise. FIG. 22B shows atwo-dimensional array of treatment spots 62 formed by manually scanningan array of beams 30 onto the skin, e.g., by pulsing laser diode bar 14Bwhile device 10 is moved across the skin in the indicated direction,e.g., in a gliding mode or stamping mode operation. Each pulse of thelaser diode bar 14B generates a linear array 66 of treatment spots 62,such that moving device 10 in a direction generally perpendicular to thelinear array 66 provided by each pulse creates a two-dimensional array68 of treatment spots 62. Device 10 may be glided across the skin anysuitable number of times and in any suitable direction(s) to cover adesired treatment area.

FIG. 23A illustrates a partial three-dimensional view of laser diodebars 14B and a window 44 for an embodiment of device 10 includingmultiple laser diode bars 14B arranged parallel to each other (e.g., toform a “stack”). Each emitter 80 of each laser diode bar 14B may act asa discrete beam source that generates a discrete laser beam 60, with themultiple beams 60 of the multiple laser diode bars 14B forming atwo-dimensional array of spaced-apart treatment spots 62 on the skin,and thus a corresponding linear array of spaced-apart MTZs 64 in theskin.

As discussed above, laser diode bars 14B may be controlled to deliverpulsed radiation, continuous wave (CW) radiation, or otherwise. In apulsed embodiment, the multiple laser diode bars 14B may be pulsedsimultaneously, time-sequentially in any defined order (or in randomorder), or in any other manner. FIG. 23B shows a two-dimensional arrayof treatment spots 62 formed by manually scanning an array of beams 30onto the skin, e.g., by pulsing laser diode bars 14B while device 10 ismoved across the skin in the indicated direction, e.g., in a glidingmode or stamping mode operation. In this example, the multiple laserdiode bars 14B are pulsed simultaneously. Thus, each pulse of the laserdiode bar 14B generates a two-dimensional array 67 of treatment spots62, and the combination of moving device 10 and pulsing the multiplelaser diode bars 14B creates a larger two-dimensional array 68 oftreatment spots 62 extending in the direction of the device movement.Device 10 may be glided across the skin any suitable number of times andin any suitable direction(s) to cover a desired treatment area.

The example embodiments of FIGS. 22A-23B may utilize “low fill-factor”laser diode bars that provide sufficient spacing between adjacentemitters 80 for providing the resulting spaced-apart treatment spots 62on the skin. In contrast, FIGS. 24A-24B include a “high fill-factor”laser diode bar that promotes the combination of the individual beams toform a single contiguous treatment spot 62 on the skin. In particular,the multiple beams emitted by the multiple emitters of the highfill-factor laser diode bar may combine during their propagation to theskin (due to the divergence of the individual beams) to form a singlecontiguous treatment spot 62.

As used herein, “high fill-factor” means a fill-factor of at least 50%,as compared to a “low-fill factor,” defined as a fill-factor of lessthan 50%. The fill factor is defined as the total emitter active portionof the laser diode bar divided by the width of the entire laser diodebar, as defined in greater detail in co-pending U.S. Provisional PatentApplication 61/563,491, the entire contents of which are herebyincorporated by reference. For some applications, using high fill-factorlaser diode bars may provide one or more advantages as compared to lowfill-factor laser diode bars. For example, a high fill-factor laser barmay provide a more uniform radiation image at the target surface. Thebeam profile from the high fill-factor laser diode bar, even in certainclose proximity arrangements, is a substantially uniform line segment.Such uniform line segment may be suitable or desirable for certainapplications or treatments, e.g., a gliding treatment normal to the linesegment direction (e.g., for laser hair removal, bulk heating skintightening, or other suitable treatments). In some embodiments, the highfill-factor laser diode bar may be used in conjunction with a sensor(e.g., a displacement sensor or a motion/speed sensor) to allow atreatment dose to be metered uniformly over a relatively large area.

FIG. 24A illustrates an embodiment similar to that of FIG. 22A, butusing a high fill-factor laser diode bar 14C. As shown, the beams 60emitted by the multiple emitters 80 of the laser diode bar 14C combinewith each other during their propagation to the skin to form a singlecontiguous treatment spot 62, and a corresponding single contiguous MTZ64. FIG. 24B illustrates an example contiguous treatment spot 62generated by laser diode bar 14C. Laser diode bar 14C may be pulsed, mayprovide continuous wave (CW) radiation, or may be otherwise controlled,in combination with movement of device 10 across the skin (e.g., in agliding mode or stamping mode operation) to provide the desired size,shape, and pattern of treatment spots 62 suitable for the particulardermatological treatment, e.g., as described in more detail inincorporated co-pending U.S. Provisional Patent Application 61/563,491.

As discussed above, in some embodiments of device 10, laser diode bars(e.g., laser diode bars 14B/14C) may be configured for “direct exposure”radiation, “close proximity” radiation, or both, as such terms aredefined and discussed herein. Further, laser diode bars may be arrangedin any of the various configurations discussed herein regarding othertypes of radiation sources, e.g., laser diode bars may be arranged inany of the various configurations shown in FIGS. 10-16 with respect toembodiments including edge emitting laser diodes.

FIGS. 25 and 26 illustrate an example embodiment of device 10 in whichthe radiation source 14 is laser diode bar including an array of 19laser emitters 80 that emit an array of beams 60 to generate an array oftreatment spots 62 in a single pulse. The device can be constructed as afully solid-state device with no optics or moving parts. Because thelaser diode bar generates multiple treatment spots 62 in each pulse, thedevice may achieve faster treatment rate and may be less expensive perspot relative to a device using a single-emitter laser diode and/or maydeliver a preferred dot pattern, such as more uniform spacing or reducedblurring or smearing of the spots, when manually moved across the skin.

VCSEL Lasers

As discussed above, in some embodiments, device 10 includes one or moreVCSEL (Vertical Cavity Surface Emitting Laser) lasers for generating oneor more treatment beams. A VCSEL may be configured to generate a singleenergy beam (e.g., as shown in FIGS. 27-29) or multiple discrete energybeams (e.g., as shown in FIGS. 30-34). In some embodiments, a VCSEL canbe configured to generate an array (1D or 2D) of discrete laser beamsfor creating an array (1D or 2D) of spaced-apart treatment spots 62 onthe skin, e.g., to provide a fractional treatment.

FIG. 27 illustrates a simplified cross-sectional side view of an exampleembodiment of device 10 that includes a VCSEL 14D configured to generatea single energy beam for providing a single treatment spot 62 on theskin. VCSEL 14D may include an array 84 of micro-emitters 86, as shownin FIG. 29, which shows an emitter surface view of the example VCSEL 14Din the direction of arrow 28 shown in FIG. 27. Each micro-emitter 86emits a divergent micro-beam, and the array of micro-beams combine (dueto the divergence of the individual micro-beams) to form a single,generally uniform beam 60 for delivery to the skin, as shown in FIG. 27.Thus, in such embodiments, the micro-emitter array 84 acts as a singlebeam source to generate a single beam 60 that creates a single treatmentspot 62 on the skin.

For at least some VCSELs, each micro-emitter 86 emits a circularlysymmetrical micro-beam. For example, each micro-emitter 86 may emit amicro-beam having an axially-symmetric divergence angle of above 20°(e.g., conventional VCSELs), or a divergence angle of between 10° and20° (e.g., certain surface relief and antiresonant reflecting opticalwaveguide structures), or a divergence angle of between 7° and 10°, or adivergence angle of below 7° (e.g., certain holey structures, such asphotonic crystals and multi-leaf structures), or a divergence angle ofabout 6° (e.g., certain multi-leaf VCSELs), or a divergence angle ofbelow 6°, e.g., between 5.1° and 5.5° (for certain photonic crystalvertical-cavity surface-emitting laser (PC-VCSEL)), e.g., as describedin “Reduction of the Far-Field Divergence Angle of an 850 nm Multi-LeafHoley Vertical Cavity Surface Emitting Laser,” Zhou Kang et al., CHIN.PHYS. LETT. Vol. 28, No. 8 (2011) 084209; and “Reduced divergence angleof photonic crystal vertical-cavity surface-emitting laser,” Anjin Liuet al., Appl. Phys. Lett. 94, 191105 (2009); doi:10.1063/1.3136859.

Micro-emitter array 84 may have any suitable shape, size, andconfiguration, and may include any suitable number of micro-emitters 86arranged in any suitable pattern to form any suitable one-dimensional ortwo-dimensional array 84. For example, the micro-emitters 86 in an array84 may be evenly spaced from each other, e.g., to provide a beam 60having a generally uniform intensity profile, or may be unevenly spacedfrom each other, e.g., to provide abeam 60 having a selected non-uniformintensity profile suitable for a particular application or treatment.For example, micro-emitters 86 towards the outside of the array 84 maybe spaced further apart from each other to provide a more rounded (i.e.,less flat-topped or top hat-like) beam intensity profile, which may besuitable for particular applications or treatments. As another example,micro-emitters 86 towards the inside of the array 84 may be spacedfurther apart from each other to provide a more cusped beam intensityprofile having a dip in intensity level near the center of the profile,which may be suitable for particular applications or treatments.Similarly, the emitters could be distributed to produce a flat-topped orGaussian beam profile. Micro-emitters 86 may be arranged in any othersuitable manner to provide any other desired beam intensity profile.

FIG. 29 illustrates a simplified cross-sectional side view of an exampleembodiment of device 10 that includes a single-beam-source VCSEL 14D(e.g., as discussed above regarding FIGS. 27-28) and an optic 78downstream of the VCSEL. Optic 78 may be any type of lens (e.g.,concave, convex, ball lens, cylindrical lens, aspherical lens, etc.) orother optic for affecting the radiation emitted by VCSEL 14D as desired.For example, optic 78 may be provided e.g., to increase or decrease thedivergence of the resulting beam 60 delivered to the skin, such as toprovide a desired spot size or shape, energy intensity level at theskin, and/or to provide increased eye safety. The downstream optic(s)may be provided directly on the VCSEL(s) via coatings, MEMs structuresor otherwise, an may be monolithic with the VCSEL(s). Other opticsexamples are a microlens array, fiber(s), or fiber bundles, amongothers.

FIGS. 30-34 illustrate embodiments that include a VCSEL configured togenerate an array (1D or 2D) of multiple discrete laser beams forcreating an array (1D or 2D) of multiple spaced-apart treatment spots 62on the skin, e.g., to provide a fractional treatment. FIG. 30illustrates an emitter surface view of an example VCSEL 14D in whichmicro-emitters 86 are arranged in an array (in this example, a 3×3two-dimensional array) of discrete micro-emitter zones 88, eachincluding a number of micro-emitters 86. Each micro-emitter zone 88 actsas a single beam source to provide a single discrete beam 60 fordelivery to the skin. In particular, the micro-beams emitted by themicro-emitters 86 in each particular zone 88 combine (due to thedivergence of the individual micro-beams) to form a single, discretebeam 60. Thus, the 3×3 array of discrete spaced-apart micro-emitterzones 88 forms a 3×3 array of discrete beam sources that generate a 3×3array of discrete spaced-apart beams 60, which provide a corresponding3×3 array of discrete spaced-apart treatment spots 62 on the skin, e.g.,for providing a fractional treatment.

The micro-emitter zones 88 may be separated from each by non-activeregions of the VCSEL chip, which regions may be formed by knownphotolithographic techniques. Each micro-emitter zone 88 may have anyshape and size, and may include any number of micro-emitters 86 arrangedin any suitable pattern to form any suitable one-dimensional ortwo-dimensional array of micro-emitters 86. For example, in someembodiments in which VCSEL is configured for pulsed radiation, each zone88 may be shaped to provide a desired treatment spot size and/or shape,taking into consideration an assumed rate of movement of the device 10across the skin during the pulsed radiation. Thus, for instance, toprovide treatment spots 62 having a generally symmetrical shape (e.g.,generally circular or square), each zone 88 may be elongated in thedirection perpendicular to the expected glide direction of the device10, with the aspect ratio of such elongation being selected based on anexpected glide speed or range of glide speeds of the device 10. Thezones may also be created by masking certain regions, such as byoverlaying an opaque material, or by using optics, such as microlensarray, or any other suitable means. As with uniform VCSELs, optics maybe monolithic to the VCSEL and built with coatings, such asspun-on-glass, or MEMs, or other means.

Further, as discussed above regarding the single-beam-source VCSEL, themicro-emitters 86 in an array 84 may be evenly spaced from each other,e.g., to provide a beam 60 having a generally uniform intensity profile,or may be unevenly spaced from each other, e.g., to provide a beam 60having a selected non-uniform intensity profile suitable for aparticular application or treatment.

In addition, VCSEL 14D may include any suitable number of micro-emitterzones 88 arranged in any suitable pattern to form any suitableone-dimensional or two-dimensional array of zones 88. Zones 88 mayevenly spaced from each other, e.g., to provide a generally uniformarray of beams 60, or may be unevenly spaced from each other, e.g., toprovide a non-uniform array of beams 60 for a particular application ortreatment.

FIG. 31 a simplified cross-sectional side view of an example embodimentof device 10 that includes the example multi-beam-source VCSEL 14D ofFIG. 30. In particular, the figure shows one row of the 3×3 array ofmicro-emitter zones 88, which row generates three discrete, spaced-apartbeams 60 for delivery to the skin.

FIG. 32 illustrates an example array of treatment spots 62 generated bythe example VCSEL 14D shown in FIG. 30, e.g., as arranged in a device 10as shown in FIG. 31. FIG. 33 illustrates an example one-dimensionalarray of treatment spots 62 generated by another example VCSEL having aone-dimensional array of (in this example, four) micro-emitter zones 88.As discussed above, VCSEL 14D may be configured to provide any othersuitable one-dimensional or two-dimensional array of treatment spots 62by designing micro-emitter zones 88 as desired.

FIG. 34 a simplified cross-sectional side view of an example embodimentof device 10 that includes a multi-beam-source VCSEL 14D (e.g., theVCSEL shown in FIG. 30), with a micro-lens array 79 for affecting eachbeam 60 generated by the various micro-emitter zones 88. Micro-lensarray 79 may include an array of optical elements corresponding to thearray of micro-emitter zones 88 of the particular VCSEL 14D, with eachoptical element of the array corresponding to one zone 88 of VCSEL 14D(and thus one beam 60). The optical elements of the micro-lens array 79may be discrete elements or may be formed as a contiguous structure,e.g., as shown in FIG. 34. Each optical element of the array 79 maycomprise any type of lens (e.g., concave, convex, ball lens, cylindricallens, aspherical lens, etc.) or other optic for affecting thecorresponding beam 60 as desired. For example, each optical element ofarray 79 may be provided to increase or decrease the divergence of theresulting beam 60 delivered to the skin, such as to provide a desiredspot size or shape, energy intensity level at the skin, and/or toprovide increased eye safety.

In some embodiments, each micro-emitter zone 88 of a multi-beam-sourceVCSEL may be independently addressable or controllable, e.g., byindependently controlling the current applied to each micro-emitter zone88. For example, zones 88 may be independently turned on/off or pulsed,or activated at different power levels. For pulsed embodiments, thevarious pulsing parameters for each zone 88, e.g., pulse on time, pulseoff time, pulse frequency, pulse duration, pulse profile, intensity,power level, etc., may be controlled independent of the other zones 88.Thus, for instance, the multiple zones 88 may be controlled to deliverpulsed beams 60 (and create corresponding treatment spots 62) in anyspatial or sequential order, e.g., according to a defined algorithm,semi-randomly, or randomly.

In some embodiments, device 10 may include a single VCSEL for providingone or multiple beams 60, as discussed above. In other embodiments,device 10 may include multiple VCSELs, each providing one or multiplebeams 60. Multiple VCSELs may be arranged in any suitable manner indevice 10, e.g., in any suitable one-dimensional or two-dimensionalarray.

In some embodiments of device 10, VCSEL(s) may be configured for “directexposure” radiation, “close proximity” radiation, or both, as such termsare defined and discussed herein. Further, VCSEL(s) may be arranged inany of the various configurations discussed herein regarding other typesof radiation sources, e.g., VCSEL(s) may be arranged in any of thevarious configurations shown in FIGS. 10-16 with respect to embodimentsincluding edge emitting laser diodes or configured with sensors, such asdisplacement, velocity, or contact, or configured for eye safety, suchas Class 1M or better per IEC 60825, and other features disclosedherein. Some embodiments that use VCSEL(s) as radiation source(s) mayinclude a diffuser or other element(s) or configuration to increase theeye safety aspects of such devices, e.g., depending on the beamdivergence of the particular VCSELs, the configuration of micro-emitters86 and emitter zones 88, and/or one or more operational parameters ofdevice 10, e.g., pulse parameters, output fluence, etc.

Like edge emitting laser diodes 14A and laser diode bars 14B/14Cdiscussed above, VCSELs 14D may be controlled to deliver pulsedradiation, continuous wave (CW) radiation, or otherwise. Thus,embodiments of device 10 including one or more VCSELs can generate one-or two-dimensional arrays of treatment spots 62 by manually scanning aseries of beams 30 onto the skin, e.g., by pulsing the VCSEL(s), or theindividual micro-emitter zones 88 of the VCSEL(s) while device 10 ismoved across the skin, e.g., in a gliding mode or stamping modeoperation. The device 10 may be glided across the skin any suitablenumber of times and in any suitable direction(s) to cover a desiredtreatment area.

Eye Safety

Some embodiments of device 10 provide eye safe radiation, by deliveringa substantially divergent energy beam 60 (e.g., using an edge emittinglaser diode with no downstream optics), and/or using an eye safetycontrol system including one or more sensors 26, and/or by any othersuitable manner. For example, in some laser-based embodiments orsettings (including certain direct exposure embodiments and certaindirect exposure embodiments), device 10 meets the Class 1M or better(such as Class 1) eye safety classification per the IEC 60825-1,referred to herein as “Level 1 eye safety” for convenience. In otherlaser-based embodiments or settings (including certain direct exposureembodiments and certain direct exposure embodiments), the device fallsoutside the IEC 60825-1 Class 1M eye safety classification by less than25% of the difference to the next classification threshold, referred toherein as “Level 2 eye safety” for convenience. In still otherlaser-based embodiments or settings (including certain direct exposureembodiments and certain direct exposure embodiments), the device fallsoutside the IEC 60825-1 Class 1M eye safety classification by less than50% of the difference to the next classification threshold, referred toherein as “Level 3 eye safety” for convenience. In some lamp-basedembodiments, the device meets the “Exempt” or “Low Risk” eye safetyclassification per the IEC 62471.

Some laser-based embodiments of device 10 configured for direct exposure(and/or close proximity exposure) of laser radiation provide Level 3 eyesafety as defined above; some laser-based direct exposure embodimentsprovide Level 2 eye safety as defined above; and some laser-based directexposure embodiments provide Level 1 eye safety as defined above. Somelaser-based embodiments of device 10 configured for indirect exposure(and/or close proximity exposure) of laser radiation provide Level 3 eyesafety as defined above; some laser-based direct exposure embodimentsprovide Level 2 eye safety as defined above; and some laser-based directexposure embodiments provide Level 1 eye safety as defined above.

Such levels of eye safety may be provided based on a combination offactors, including for example, (a) the divergence of the beam, (b) thepulse duration, (c) the emitted power, (d) the total energy per pulse,(e) the wavelength of the emitted beam, and/or (f) the arrangement ofthe laser beam source. Thus, in some embodiments (including certaindirect exposure, close proximity embodiments; certain direct exposure,remote proximity embodiments; certain indirect exposure, close proximityembodiments; and certain indirect exposure, remote proximityembodiments), one, some, or all of such factors may be selected oradjusted to provide Level 1, Level 2, or Level 3 eye safety, as definedabove.

Certain beam sources discussed herein generate divergent (and in somecases, highly divergent) radiation in at least one axis, which mayincrease the eye safety aspect of embodiments that employ such beamsources. For example, a typical edge emitting laser diode diverges inboth a fast axis and a slow axis, which may to provide

Level 1, Level 2, or Level 3 eye safety, depending on the other selectedparameters. An analysis of relevant issues is discussed below.

Highly divergent intense light source can be eye safe if it meets theIEC 60825-1 Class 1M AEL (Accessible Emission Limit) specification. WithClass 1M classification, the source is generally only potentiallyharmful if an intervening optics is deliberately placed in between thesource and the eye. For the typical wavelength greater than 1400 nm usedin fractional laser treatment, the light source is also greatlyattenuated by the water absorption in the eye anterior chamber. Hencethere is substantially little or no retinal hazard in this wavelengthrange. The emission limit is determined by the potential corneal damage.The accessible emission limit for Class 1M source in the wavelengthrange of 1400 to 1500 nm and 1800 to 2600 nm is described by a simpleequation in Table 4 of IEC 60825-1:2007:

AEL=4.4t ^(0.25) mJ  Equation 1

AEL energy is measured at 70 mm from the source with a circular apertureof 7 mm in diameter (Condition 2 measurement setup described in Table 11of IEC 60825-1:2007, applicable for diverging beam). In this equation, t(in unit of seconds) is the source pulse duration in the range of 1 msto 350 ms. For a typical single beam laser diode source, this pulseduration is in the range of 1 to 10 ms. Therefore, the corresponding AELis 0.8 to 1.4 mJ.

The actual source AE (Accessible Energy) can be estimated for a givenbeam divergent characteristics. It can also be measured experimentallywith the appropriate aperture stop (7-mm wide) and measurement distance(70-mm from the source). The AE at a distance 70-mm from the treatmentaperture is given by (this is approximately correct for a Gaussian beamfrom a diffraction limited laser):

AE=2.5×10⁻³ Q/[tan(Φ_(F)/2)tan(Φ_(S)/2)]mJ  Equation 2

where Q (in unit of mJ) is the source energy at the treatment plane, andΦ_(F) and Φ_(S) are the beam divergence in the fast and slow axis,respectively. To achieve the Class 1M eye safety classification, AE mustbe lower than the AEL for the corresponding pulse duration.

Table 6 below provides several example configurations and devicesettings for providing Level 1 eye safety (Class 1M or better perstandard IEC 60825-1) for certain embodiments of device 10.

TABLE 6 Specific Specific Example Example of Example Example ofParameter Embodiment 1 Embodiment 1 Embodiment 2 Embodiment 2Configuration direct exposure direct exposure indirect indirect (nooptics) (no optics) exposure (with exposure (with optic) optic)Radiation Single beam Single beam Single beam Single beam source edgeemitting edge emitting edge emitting edge emitting laser diode laserdiode laser diode laser diode w/ w/collimating collimating optics opticswavelength 1400-1500 nm 1400-1500 nm 1400-1500 nm 1400-1500 nm or1800-2600 nm or 1800-2600 nm or 1800-2600 nm or 1800-2600 nm beam35°-45° fast 45° fast axis 2°-12° fast 12° fast axis divergence at axis,10° slow axis axis, 12° slow axis skin surface 6°-12° slow 6°-12° slow(fast axis, slow axis axis axis) Pulse duration 1-8 about 3 1-15 about 5(ms) Power (W) 2-6 about 4 1-4 about 1 Total energy  5-15 about 12  5-15about 5 per pulse (mJ) AEL (mJ) 0.8-1.3 about 1.0 0.8-1.5 about 1.2 AE(mJ) 0.3-2.3 about 0.8 1.1-41  about 1.1 Eye safety Class 1 M for Class1M Class 1M for Class 1M classification AE < AEL AE < AEL

Because certain embodiments or device settings may provide Level 1,Level 2, or Level 3 eye safety based on the appropriate selection ofparameters discussed above, in some such embodiments an eye safetysensor or system may be omitted. However, some such embodiments, eventhose providing Level 1 eye safety, may include an eye safety sensor orsystem to provide redundancy, to meet particular regulatory standards,or for other reasons.

In at least some embodiments additional eye safety is provided byincorporating a contact sensor that enables pulsing of the light sourceonly when in contact with the skin. Thus, in such embodiments, thelikelihood of corneal eye injury may be reduced or substantiallyeliminated unless the device is literally pressed to the eye surface.

Some embodiments may include an optical diffuser or radiation-diffusingelements or configuration (e.g., as described in U.S. Pat. No.7,250,045, U.S. Pat. No. 7,452,356, or US patent applicationPublication, all three of which are hereby incorporated by reference),one or more optics (e.g., a lens), or other elements and configurations(e.g., selected pulse durations, wavelengths, pulse repetitionfrequencies, beam profile characteristics, and beam propagationcharacteristics) to provide increased eye safety. Other embodiments mayprovide a particular eye safety level (e.g., Level 1, Level 2, or Level3 as defined above) without such elements, and in a direct exposureconfiguration (and/or close proximity configuration), due to theinherent or selected divergence of the beam source (e.g., certain laserdiodes) combined with suitable operational parameters of the beamsource, e.g., as discussed above.

Displacement-Based Control

As discussed above regarding FIG. 1, device 10 may include controlsystems 18 configured to control various controllable operationalparameters of device 10 (e.g., operational aspects of radiation engine12, fans 34, displays 32, etc.). In some embodiments, control systems 18may include a displacement monitoring and control system 132(“displacement-based control system 132” for short) configured todetermine the displacement of device 10 relative to the skin if or asdevice 10 is moved across the surface of the skin (e.g., while operatingdevice 10 in a gliding mode or a stamping mode), and control one or morecontrollable operational parameters of device 10 based on the determineddisplacement. For example, displacement-based control system 132 maycontrol one or more operational aspects of radiation source(s) 14, suchas for example, controlling the radiation mode of radiation source(s)14, controlling the on/off status of radiation source(s) 14, controllingthe timing of such on/off status (e.g., pulse-on time, pulse-off time,pulse duty cycle, pulse frequency), controlling parameters of theradiation (e.g., wavelength, intensity, power, fluence, etc.),controlling parameters of optics 16, and/or any other controllableoperational parameters of device 10.

In some embodiments, displacement-based control system 132 may alsoprovide feedback to the user via display 32 and/or one or more userinterfaces 28 based on the monitored displacement of device 10 and/orthe automatic control of one or more controllable operational parametersby system 132. For example, system 132 may provide audio and/or visualfeedback to the user indicating data detected, or actions taken, bysystem 132, e.g., feedback indicating whether or not the displacement ofdevice 10 exceeds a predetermined threshold distance, feedbackindicating that treatment radiation source 14 has been turned on or off,feedback indicating that system 132 has automatically changed theradiation mode or other parameter of treatment radiation source 14, etc.

Displacement-based control system 132 may include, utilize, or otherwisecooperate with or communicate with any one or more of the controlsubsystems 52 discussed above with respect to FIG. 2 (e.g., radiationsource control system 130, and user interface control system 134,including user interface sensor control subsystem 140 and userinput/feedback control subsystem 142), as well as control electronics30, any one or more sensors 46, user interfaces 28, and displays 32.

FIG. 35 illustrates a block diagram of a displacement-based controlsystem 132, according to certain embodiments. Displacement-based controlsystem 132 may be provided in any of the embodiments of device 10discussed herein. As shown, displacement-based control system 132 mayinclude a displacement sensor 100, control electronics 30, and treatmentradiation source 14 and/or display 32. In general, displacement sensor100 collects data regarding the displacement of device 10 relative tothe skin 40 and communicates such data to control electronics 30, whichanalyzes the data and controls or provides feedback via one or more oftreatment radiation source 14 and display 32. In some embodiments,control electronics 30 may also analyze particular user input receivedvia one or more user interfaces 28 in conjunction with data receivedfrom sensor 100. For example, the appropriate control or feedbackprovided by control electronics 30 (e.g., as defined by a relevantalgorithm 154) may depend on the current operational mode and/or othersettings selected by the user. For instance, the minimum thresholddisplacement for triggering particular responses by control electronics30 may depend on the current operational mode selected by the user.

Control electronics 30 may include any suitable logic instructions oralgorithms 154 stored in memory 152 and executable by one or moreprocessors 150 (e.g., as discussed above regarding FIG. 1) forperforming the various functions of displacement-based control system132. Displacement sensor 100 may be configured for detecting, measuring,and/or calculating the displacement of device 10 relative to the skin40, or for generating and communicating signals to control electronics30 for determining the displacement of device 10. In some embodiments,e.g., as discussed below with reference to FIGS. 40-43, displacementsensor 100 may be a single-pixel sensor configured to identify and countintrinsic skin features in the skin, and determine a displacement of thedevice 10 across the skin based on the number of identified intrinsicskin features. As used herein, “intrinsic skin features” include both(a) surface features of the skin, e.g., textural roughness, follicles,and wrinkles, and (b) sub-surface features, e.g., vascularity andpigmentation features.

In other embodiments, e.g., as discussed below with reference to FIG.45, displacement sensor 100 may be a multiple-pixel sensor, such as amouse-type optical sensor utilizing a two-dimensional array of pixels.

Depending on the particular embodiment, displacement sensor 100 (or acombination of multiple displacement sensors 100) may be used for (i)detecting, measuring, and/or calculating displacements of device 10 inone or more directions, or (ii) detecting, measuring, and/or calculatingthe degree of rotation traveled by device 10 in one or more rotationaldirections, or (iii) any combination thereof.

Displacement-based control system 132, and in particular controlelectronics 30, may control one or more controllable operationalparameters of device 10 (e.g., operational aspects of treatmentradiation source 14, fans 34, displays 32, etc.) to achieve any of avariety of goals. For example, control electronics 30 may controltreatment radiation source 14 (a) in order to avoid overtreatment of thesame area of skin, (b) to provide desired spacing between adjacent orsequential treatment spots 62 or arrays of spots 62, (c) to generate arelatively uniform pattern, or other desired pattern, of treatment spots62, (d) to restrict the delivery of radiation to particular tissue, suchas human skin (i.e., to avoid delivering radiation to eye or to othernon-skin surfaces), (e) and/or for any other suitable goals, and (f) andcombination of the above.

In some embodiments, displacement-based control system 132 may be usedin both a gliding mode and a stamping mode of device 10.

FIG. 36 illustrates a flowchart of an example method 400 for controllingdevice 10 using displacement-based control system 132, while device 10is used either in a gliding mode or a stamping mode, according tocertain embodiments. At step 402, device 10 pulses the beam source(s) ofdevice 10, to generate one or more treatment spots 62 on treatment area40. If device 10 is being used in a gliding mode, the user may glidedevice 10 across the skin during the first pulse of the beam source(s).If device 10 is being used in a stamping mode, the user may hold device10 stationary on the skin during the first pulse of the beam source(s).

At step 404, displacement-based control system 132 performs a firstmonitoring process to monitor and analyze the displacement of device 10across the surface of the skin using displacement sensor 100. Forexample, as discussed below, displacement-based control system 132 mayanalyze signal 360 to identify and count intrinsic skin features 70 inthe skin (e.g., in embodiments utilizing a single-pixel displacementsensor 100 (e.g., sensors 100A, 100B, or 100C discussed below)), orcompare images scanned at different times (in embodiments utilizing amulti-pixel displacement sensor 100 (e.g., sensor 100D discussedbelow)), as device 10 is moved across the skin (e.g., in a gliding mode,during and/or after the first pulse of the beam source(s); or in astamping mode, after the first pulse of the beam source(s)). System 132may begin the first monitoring process at the initiation or conclusionof the first pulse of the beam source(s) or upon any other predefinedevent or at any predetermined time.

At step 406, displacement-based control system 132 controls the pulsingof the beam source(s) based on the displacement of device 10 determinedat step 404. For example, in some embodiments, displacement-basedcontrol system 132 initiates a second pulse of the beam source(s) upondetermining that device 10 has moved a particular predetermined distanceacross the skin (e.g., 3 mm). Thus, in such embodiments, a substantiallyconstant spacing (e.g., 3 mm) between successive treatment spots 62 inthe glide direction can be achieved regardless of the manual glidespeed. Thus, the pulse frequency may vary dynamically as a function ofthe manual glide speed.

In other embodiments, device 10 (or the user) sets a defined pulsefrequency (e.g., 15 Hz), as well as a predefined minimum devicedisplacement for providing a predefined minimum spacing betweensuccessive treatment spots 62 in the glide direction (e.g., 1 mm).Displacement-based control system 132 analyzes the monitoreddisplacement of device 10 determined at step 404 and the defined pulsefrequency to determine whether the providing the next pulse according tothe defined pulse frequency would violate the minimum spot spacing(e.g., 1 mm). If not, displacement-based control system 132 allowsdevice 10 to continue pulsing at the defined pulse frequency. However,if so (i.e., if providing the next pulse according to the defined pulsefrequency would violate the minimum spot spacing), displacement-basedcontrol system 132 may control radiation source 14 to delay the nextpulse at least until system 132 determines that the minimum devicedisplacement has been achieved (thus ensuring the predefined minimumspacing between successive treatment spots 62), or system 132 may othercontrol radiation source 14 to prevent over-treatment (e.g., decreasingthe beam intensity, turning off radiation source 14, providing feedbackto the user, etc.)

Single Pixel Displacement Sensor

FIG. 37 illustrates an example single-pixel displacement sensor 100A foruse in displacement-based control system 132, according to certainembodiments. Displacement sensor 100A includes a light source 310A, alight detector 312A, a light guide 313 having an input and outputportions 314 and 316, a half-ball lens 318, a ball lens 320, a housing322 for housing at least lenses 318 and 320 (and/or other components ofsensor 100A), and a and a microcontroller 330.

Light source 310A may be a light-emitting diode (LED) or any othersuitable light source. Light source 310A may be selected for detectingfine details in the surface or volume of human skin. Thus, a wavelengthmay be selected that penetrates a relatively shallow depth into the skinbefore being reflected. For example, light source 310A may be a blue LEDhaving a wavelength of about 560 nm, or a red LED having a wavelength ofabout 660 nm, or an infrared LED having a wavelength of about 940 nm.Red or infrared wavelength LEDs are relatively inexpensive and work wellin practice. Alternatively, a semiconductor laser or other light sourcecould be used.

Light detector 312A may be a photodiode, phototransistor, or other lightdetector. In some embodiments, a phototransistor has sufficient currentgain to provide a directly usable signal, without requiring additionalamplification.

Light guide 313 is configured to guide light from light source 310A (viainput portion 314) and guide light reflected off the skin to detector312A (via output portion 316). Input portion 314 and output portion 316may comprises optical fibers or any other suitable light guides. Lightguide 313 may be omitted in some embodiments in which light source 310Aand detector 312A are close enough to the skin surface to image orconvey the light directly onto the skin surface, or alternatively usingsuitable optics to image or convey light source 310A and detector 312Adirectly onto the skin surface.

Microcontroller 330 may be configured to drive light source 310A andreceive and analyze signals from light detector 312A. Microcontroller330 may include an analog-to-digital converter (ADC) 332 for convertingand processing analog signals from light detector 312A.

In operation of this embodiment, light (for example, visible or near-IRenergy) from light source 310A travels down input light guide 314 andthrough half-ball lens 318 and ball lens 320, which focuses the light onthe skin surface 32. Some of this light is reflected and/or remitted bythe skin and returns through ball lens 320, half-ball lens 318, andoutput light guide 316, toward light detector 312A, which converts thelight into an electrical signal, which is then delivered tomicrocontroller 330. The light may be modulated to permit discriminationof a constant background ambient illumination level from the local lightsource.

Detector 312A may deliver analog signals to microcontroller 330, whichmay convert the signals to digital signals (using integrated ADC 332 orsuitable alternatives), and perform computations regarding on theamplitude of the recorded signal over time to identify and countfeatures in the skin and determine a relative displacement device 10accordingly, as discussed below.

The amount of light that is returned to detector 312A is a strongfunction of the distance “z” between the sensor optics and skin surface32. With no surface present only a very small signal is generated, whichis caused by incidental scattered light from the optical surfaces. Inaddition to displacement sensor, this characteristic can be exploited toprovide a contact sensor in another embodiment. When the skin surface 32is within the focal distance of the lens 320, a much larger signal isdetected. The signal amplitude is a function of distance z as well assurface reflectivity/remittance. Thus, surface texture features on theskin surface create a corresponding signal variation at detector 312A.Microcontroller 330 is programmed to analyze this signal and identifyintrinsic skin features 70 that meet particular criteria.Microcontroller 330 may count identified features and determine anestimated displacement of sensor 100A relative to the skin 40 in thex-direction (i.e., lateral displacement), based on knowledge ofestimated or average distances between intrinsic skin features 70 forpeople in general or for a particular group or demographic of people, asdiscussed below.

Displacement sensor 100A as described above may be referred to as a“single-pixel” displacement sensor 100A because it employs only a singlereflected/remitted beam of light for generating a single signal 360,i.e., a single pixel. In other embodiments, displacement sensor 100 maybe a multi-pixel sensor that employs two pixels (i.e., two reflectedbeams of light for generating two signals 360), three pixels, fourpixels, or more. Multi-pixel displacement sensors 100 may be configuredsuch that the multiple pixels are arranged along a single lineardirection (e.g., along the glide direction, the scan direction, or anyother direction), or in any suitable two-dimensional array (e.g., acircular, rectangular, hexagonal, or triangular pattern).

FIG. 38 illustrates another example single-pixel displacement sensor100B for use in displacement-based control system 132, according tocertain embodiments. Displacement sensor 100B includes a light source310B, a light detector 312B, optics 342, and a microcontroller 330.

Light source 310B and light detector 312B may be provided in anintegrated emitter-detector package 340, e.g., an off-the-shelf sensorprovided by Sharp Microelectronics, e.g., the Sharp GP2S60 CompactReflective Photointerrupter. Light source 310B may be similar to lightsource 310A discussed above, e.g., a light-emitting diode (LED) or anyother suitable light source. Light detector 312B may be similar to lightsource 310A discussed above, e.g., a photodiode, phototransistor, orother light detector.

Optics 342 may include one or more optical elements for directing lightfrom light source 310B onto the target surface and for directing lightreflected/remitted from the target surface toward light detector 312B.In some embodiments, optics 342 comprises a single lens element 342including a source light focusing portion 344 and a reflected lightfocusing portion 346. As shown, source light focusing portion 344 maydirect and focus light from light source 310B onto the skin surface 38,and reflected light focusing portion 346 may direct and focus reflectedlight onto detector 312B. Lens element 342 may have any suitable shapefor directing and focusing the source light and reflected light asdesired.

Microcontroller 330 may be configured to drive light source 310B andreceive and analyze signals from light detector 312B. Microcontroller330 may include an analog-to-digital converter (ADC) 332 for convertingand processing analog signals from light detector 312B.

The operation of sensor 100B—including the operation of light detector312B and microcontroller 330—may be similar to that described above withreference to sensor 100A of FIG. 37. That is, detector 312B may record asignal having an amplitude or other property that corresponds to adistance z perpendicular to the target surface or other propertiesindicative of intrinsic skin features. Detector 312B may deliver analogsignals to microcontroller 330, which may convert the signals to digitalsignals (using integrated ADC 332), and perform computations regardingthe recorded signal over time to identify and count features in the skinand determine a relative displacement of device 10 accordingly.

Like displacement sensor 100A, displacement sensor 100B may be referredto as a “single-pixel” displacement sensor 100B because it employs onlya single reflected beam of light for generating a single signal 360,i.e., a single pixel.

FIG. 39 illustrates yet another example single-pixel displacement sensor100C for use in displacement-based control system 132, according tocertain embodiments. Displacement sensor 100C is generally similar todisplacement sensor 100B shown in FIG. 38, but omits the lens element342 of displacement sensor 100B.

Displacement sensor 100C includes a light source 310C, a light detector312C, optics 342, and a microcontroller 330. Light source 310C and lightdetector 312C may be provided in an integrated emitter-detector package340, e.g., an off-the-shelf sensor provided by Sharp Microelectronics,e.g., the Sharp GP2S60 Compact Reflective Photointerrupter. Light source310C may be similar to light source 310A/310B discussed above, e.g., alight-emitting diode (LED) or any other suitable light source.Microcontroller 330 may be configured to drive light source 310C with adirect or modulated current. Light detector 312C may be similar to lightsource 310A discussed above, e.g., a photodiode, phototransistor, orother light detector.

The integrated (or non-integrated) emitter-detector package 340 may behoused in an opaque enclosure 390, having a clear aperture 392 in thefront which is covered by a window 394 (for example a transparentplastic, or glass). Infrared light from light source 310C (e.g., LED)shines through the aperture 392 and impinges on the skin surface 38.Some of this light (reflected/remitted from the skin 40, as well asscattered from the interior volume of opaque enclosure 390, returnsthrough aperture 392 and reaches detector 312C (e.g., photodetector),which converts the received light into an electrical signal. The lightmay be modulated to permit discrimination of a constant backgroundambient illumination level from the local light source.

The amount of light that is returned to detector 312C is a strongfunction of the distance “z” between the skin surface 38 and the opticalaperture 392. When the skin surface 38 is close to or in contact withwindow 394, a larger signal is detected. With no surface presented tothe detector, a smaller optical signal remains, due to reflections fromthe surface of opaque mask 390 and window 394, as well as backgroundlight from exterior illumination sources.

Thus, the signal amplitude recorded by detector 312C is a function ofz-height as well as skin reflectivity/remittance. Surface texturefeatures 70 create a corresponding signal variation at detector 312C.Detector 312C may deliver the recorded analog signals (with theamplitude being at least indicative of z-height) to microcontroller 330,which may convert the signals to digital signals (using integrated ADC332), and perform computations regarding the recorded signal over timeto identify features 70 in the skin (based on the signal amplitude),count or otherwise process such identified features 70, and determine arelative displacement of device 10 accordingly.

Integrated emitter-detector pairs used for the proximity detector may becompact, inexpensive, and readily available. It is also possible to usea separate emitter and detector. Any suitable wavelength range of lightmay be used, but infrared may be selected due to the sensitivity of thedetector 312C (e.g., phototransistor), and ability to block out visiblelight with an IR-pass filter over the detector. Also, different skintypes show more uniform reflectance levels in IR than in shorterwavelengths. Test results show that a phototransistor has sufficientcurrent gain to provide a directly usable signal to the integrated ADC332 of microcontroller 330, without requiring additional amplification.

Like displacement sensors 100A and 100B, displacement sensor 100C may bereferred to as a “single-pixel” displacement sensor 100C because itemploys only a single reflected beam of light for generating a singlesignal, i.e., a single pixel.

FIG. 40 illustrates a pair of experimental data plots for an embodimentof optical displacement sensor 100C being scanned above the skin surface38 of a human hand. The photodetector signal (y-axis) is shown versustime (x-axis) in arbitrary units. The area without dense peaks indicatestimes in which the sensor aperture 392 is held against a fixed area ofthe skin. An algorithm takes as input the photodetector signal togenerate the lower “detected output” plot, which is a signal suitablefor controlling device 10. For example, microcontroller 330 may beprogrammed to analyze the photodetector signal and identify intrinsicskin features 70 that meet particular criteria, e.g., using any of thevarious techniques or algorithms disclosed herein, or any other suitabletechniques or algorithms. In some embodiments, microcontroller 330 maycount identified features and determine an estimated displacement ofsensor 100C relative to the skin 40 in the x-direction (i.e., lateraldisplacement), based on knowledge of estimated or average distancesbetween intrinsic skin features 70 for people in general or for aparticular group or demographic of people, as discussed below.

Certain embodiments of single-pixel displacement sensor 100, e.g.,sensors 100A, 100B, and/or 100C discussed above, may not require imagingoptics, as compared to imaging-type sensors. Further, certainembodiments of single-pixel displacement sensor 100 may not requireclose proximity between the electronics (e.g., microcontroller) and thetarget surface to be sensed. For example, the light source and/ordetector may be spaced away from the target surface, with light guidesor relay optics used to convey light between the light source/detectorand the target surface. As another example, the light source and/ordetector may be spaced relative close to the target surface, but may becoupled to a relatively remote microcontroller by wiring.

Further, in certain embodiments of single-pixel displacement sensor 100,e.g., sensors 100A, 100B, and 100C discussed above, the activecomponents (e.g., light source, detector, etc.) and the active sensingarea are relatively small (e.g., as compared to a standard opticalmouse-type imaging sensor). Thus, in embodiments in which single-pixeldisplacement sensor 100 is located at the application end 42 of device10, sensor 100 may occupy relatively little real estate on theapplication end 42 (e.g., as compared to a standard optical mouse-typeimaging sensor), which may allow the total size of application end 42 tobe reduced in at least one dimension, which may be advantageous incertain embodiments.

FIG. 41 represents an example plot 350 of a signal 360 generated bydetector 312A, 312B, or 312C as sensor 100A, 100B, or 100C is movedacross the skin of a human hand in the x-direction. The x-axis of plot350 may be scaled such that the movement of the signal 360 on the x-axismatches the distance of movement of sensor 100A/100B/100C across theskin.

The amplitude of the signal 360 corresponds with the texture of the skinsurface, which includes numerous intrinsic skin features 70. As shown,signal 360 includes a series of peaks 362, valleys 364, and othercharacteristics. Intrinsic skin features 70 may be identified fromsignal 360 based on any suitable parameters or algorithms.

For example, one or more of the following criteria may be used foridentifying intrinsic skin features 70 based on signal 360:

(a) the raw amplitude of a peak 362,

(b) the amplitude of a peak 362 relative to the amplitude of one or moreother peaks 362 (e.g., one or more adjacent peaks 362),

(c) the amplitude of a peak 362 relative to the amplitude of one or morevalleys 364 (e.g., one or more adjacent valleys 364),

(d) the raw amplitude of a valley 364,

(e) the amplitude of a valley 364 relative to the amplitude of one ormore other valleys 364 (e.g., one or more adjacent valleys 364),

(f) the amplitude of a valley 364 relative to the amplitude of one ormore valleys 364 (e.g., one or more adjacent valleys 364),

(g) the rate of increase in amplitude of signal 362 (i.e., positiveslope of signal 360) for a particular portion of signal 360,

(h) the rate of decrease in amplitude of signal 360 (i.e., negativeslope of signal 360) for a particular portion of signal 362,

(i) the x-direction distance between adjacent peaks 362 (D_(I), D₂, D₃,etc),

(j) the x-direction distance between adjacent valleys 364, or

(k) any other suitable criteria.

An algorithm 154 may identify intrinsic skin features 70 based on anyone or any combination of more than one of the criteria listed above.Such algorithm 154 may include (predefined or real-time calculated)threshold values to which one or more of the criteria listed above arecompared. In some embodiments that identify intrinsic skin features 70based on peaks 362 in signal 360, the algorithm 154 may be able todistinguish major or global peaks (e.g., peaks 362) from minor or localpeaks (e.g., local peak 368), and use only the major or global peaks 362for identifying intrinsic skin features 70. As another example, thealgorithm 154 may distinguish major or global valleys (e.g., valleys364) from minor or local valleys (e.g., local valley 369), and use onlythe major or global valleys 364 for identifying intrinsic skin features70.

One example displacement algorithm that may be used with a single-pixeldisplacement sensor (e.g., sensor 100A or 100B) to identify intrinsicskin features 70, and detect displacement of device 10, is discussedbelow with reference to FIG. 42. FIG. 42 illustrates three data plots: araw signal plot 370, filtered signal plot 372, and an intrinsic skinfeature detection plot 374. The example displacement algorithm takes asinput a raw signal from a photodetector (representingreflectance/remittance vs. time), and generates as output a digitalpulse “1” when a displacement has been detected, and “0” when nodisplacement has been detected. In FIG. 42, each plot 370, 372, and 374shows the specified signals plotted against time on the horizontal axis.

Raw signal plot 370 shows the raw input signal “pd1” 376, which includesamplitude variations corresponding to displacement of the sensor acrossthe skin (the amplitude variations correspond to intrinsic skin features70 on the skin), and flatter areas corresponding to the sensor dwellingin the same place on the skin.

As shown in filtered signal plot 372, the algorithm extracts a high-passfiltered version “diff1” 378 of the raw signal pd1 and also apositive-tracking and negative-tracking envelope indicated as “max1” 380and “min1” 382, respectively. The positive envelope “max1” 380 iscreated at each point in time by adding a fraction of the currenthigh-pass-filtered positive signal “dif1p” to the previous time-stepvalue of the positive envelope signal “max1”, where “dif1p” is formedfrom the high-pass filtered signal “dif1”:

dif1p=dif1(dif1>0)

dif1p=0(dif1<0)

Similarly, the negative envelope “min1” 382 is created the same way from“dif1n”, which is the high-pass filtered negative signal:

dif1n=dif1(dif1<0)

dif1n=0 (dif1=0)

Finally, as shown in the intrinsic skin feature detection plot 374, thefeature-detect signal “d1” 384 is set to 1 at any time step in which“dif1” has a zero crossing (i.e., where previous time step and currenttime step have a different sign) AND “max1” exceeds a threshold value,AND “min1” exceeds a threshold value. Otherwise, “d1” is set to 0. Thethreshold limits may be designed to prevent non-desirable outputs (e.g.,feature-detection false positives and/or false negatives) due to randomsensor or circuit noise levels. The zero-crossing requirement may alsobe designed to prevent non-desirable outputs (e.g., feature-detectionfalse positives and/or false negatives) when the photosignal dif1 isentirely positive or negative, as when the photosensor is initiallybrought up against a surface (signal shows large increase with time), orremoved from it (signal decreases).

From feature detection plot 374, the displacement of the sensor relativeto the skin can be determined by counting the number of detectedfeatures 70. The algorithm may then make control decisions by (a)comparing the number of detected features 70 to one or morepredetermined threshold numbers (e.g., allow continued treatment if atleast three features 70 have been detected), or (b) by multiplying thenumber of detected features 70 by a known nominal or average distancebetween features 70 (e.g., as determined based on experimental testing)to determine displacement distance (e.g., in millimeters), and thencomparing the determined displacement distance to one or morepredetermined threshold distances (e.g., allow continued treatment ifthe determined displacement exceeds 2 mm). It can be appreciated by oneof ordinary skill in the art that, if desired, this embodiment couldalso be used to create a velocity sensor if rate information was alsoobtained and used or a dwell sensor.

In some embodiments, the example algorithm may be utilized in a systemincluding a single sensor (e.g., single-pixel displacement sensor 100Aor 100B) having a single detector (e.g., detector 312A or 312B). Inother embodiments, the example algorithm may be utilized in a systemwith more than one sensors (e.g., more than one sensor 100A and/or 100B)or with a sensor 100 that includes more than one detector 312 (e.g., asensor 100A or 100B including more than one detector 312A or 312B). Suchembodiments may thus generate multiple feature detection signals 384,each corresponding to a different sensor 100 or detector 312 with thesame type of features detected or different types of features detected.

In embodiments including multiple sensors 100 or detectors 312, thealgorithm may make control decisions based on the multiple featuredetection signals 384 in any suitable manner. For example, the algorithmmay generate a control signal only if each of the multiple featuredetection signals 384 detects a predetermined number of features 70(which may provide relatively greater resistance to noise or possiblefault conditions). Or, the algorithm may generate a control signal ifany of the multiple feature detection signals 384 detects apredetermined number of features 70 (which may provide relativelygreater detection sensitive for surfaces with less texture and smalleramplitude reflectance features). Or, the algorithm may generate controlsignals based on the total number of features 70 detected by themultiple feature detection signals 384. The algorithm can also bedesigned to the identify an outlier feature detection signal 384 (ascompared to the other feature detection signal 384), and ignore suchsignal 384, at least while it remains an outlier.

A sample of humans was tested with a particular embodiment of sensor100A, and identifying intrinsic skin features 70 according to theexample algorithms discussed above. The testing involved moving sensor100A in a straight line across the surface of the test subjects' skin,such as face or arm skin. The resulting test data using the particularembodiment of sensor 100A indicated that adjacent intrinsic skinfeatures 70 (texture or roughness, in this case) are located about0.3-0.4 mm apart on average. In other words, with reference to FIG. 40,the test data indicated an average spacing D₁, D₂, D₃, etc. of about0.3-0.4 mm.

The displacement of device 10 can be determined or approximated usingthis experimental data, e.g., the average spacing between intrinsic skinfeatures 70. For example, the displacement of device 10 can bedetermined or approximated by multiplying the number of intrinsic skinfeatures 70 identified by system 132 by the experimentally determinedaverage spacing between intrinsic skin features 70.

Thus, displacement-based control system 132 (in particular, controlelectronics 30) may control device 10 based on the determined orapproximated displacement of device 10 across the skin. For example,displacement-based control system 132 may control one or morecontrollable operational parameters of device 10 (e.g., operationalaspects of treatment radiation source 14) based on the number ofintrinsic skin features 70 identified by system 132 for a displacementof device 10 across the skin. For example, system 132 may control device10 to pulse the beam source(s) of device 10 (thus generating one or moretreatment spots 62) each time device 10 is displaced X mm, as determinedby identifying N intrinsic skin features 70. For example, ifexperimental data indicates that intrinsic skin features 70 are spacedby an average of 0.4 mm, system 132 may control device 10 to pulse thebeam source(s) each time device 10 is displaced approximately 1.2 mm, asdetermined by identifying three intrinsic skin features; the next pulseof the beam source(s) is not initiated delivered until/unless device 10is displaced another approximately 1.2 mm (i.e., until three intrinsicskin features 70 are identified by system 132). Additional details andexamples of the control of device 10 by system 132 are provided below.

Thus, in some embodiments, control systems 18, includingdisplacement-based control system 132, controls operational aspects ofdevice 10 (e.g., operational aspects of treatment radiation source 14)based on the displacement of device 10 across the skin, independent ofthe rate, speed, or velocity of device 10 moving across the skin. Insome embodiments device 10, including displacement-based control system132, is not configured for detecting or measuring any data indicative ofthe rate, speed, or velocity of device 10 moving across the skin, or fordetermining or attempting to determine the rate, speed, or velocity ofdevice 10 moving across the skin. Rather, device 10 is configured fordetecting or measuring data indicative of the lateral displacement ofdevice 10 relative to the skin, and for determining the lateraldisplacement of device 10 using such data, e.g., as discussed above. Inother words, device 10 can be moved at any rate, including very slowly,and pulses are delivered only if sufficient distance been translatedrelative to prior pulse location.

In other embodiments, device 10 may include a speed detection system,e.g., including a motion/speed sensor 102, for detecting or measuringdata indicative of the rate, speed, or velocity of device 10 movingacross the skin, and for determining or attempting to determine therate, speed, or velocity of device 10 based on such data. Such speeddetection sensor or system may be provided in addition to, or in placeof, displacement-based control system 132 and displacement sensor 100A.

In other embodiments, device 10 may include a dwell sensor 116 formeasuring data indicative of whether device 10 is stationary orstationary within a certain tolerance with respect to the skin. Dwellsensor 116 may employ aspects of displacement sensor 100 described abovebut may be configured to provide information specifically about whetherdevice 10 is stationary. For example, all or portions of the examplealgorithm described above for single-pixel displacement sensor 100A/100Bmay be used to determine when device 10 is substantially stationary(e.g., by recognizing the flat spots in the raw data signal 376 shown inFIG. 42) and device 10 may be controlled based on that information(e.g., radiation source 14 may be disabled if device 10 is determined tobe stationary or dwelling).

FIG. 43 illustrates a more specific example of the general method 400 ofFIG. 36. In particular, FIG. 43 illustrates a method 420 for controllingdevice 10 using displacement-based control system 132 that employs asingle-pixel displacement sensor 100A, 100B, or 100C, while device 10 isused either in a gliding mode or a stamping mode, according to certainembodiments.

At step 422, device 10 pulses the beam source(s) of device 10, togenerate one or more treatment spots 62 on treatment area 40, asdiscussed above regarding step 402. If device 10 is being used in agliding mode, the user may glide device 10 across the skin during thefirst pulse of the beam source(s). If device 10 is being used in astamping mode, the user may hold device 10 stationary on the skin duringthe first pulse of the beam source(s).

At step 424, displacement-based control system 132 performs a firstmonitoring process to monitor and analyze the displacement of device 10across the surface of the skin using single-pixel displacement sensor100A/100B/100C. For example, as discussed below, displacement-basedcontrol system 132 may analyze signal 360 to identify and maintain acount of intrinsic skin features 70 in the skin as device 10 is movedacross the skin (e.g., in a gliding mode, during and/or after the firstpulse of the beam source(s); or in a stamping mode, after the firstpulse of the beam source(s)). System 132 may begin the first monitoringprocess at the initiation or conclusion of the first pulse of the beamsource(s) or upon any other predefined event or at any predeterminedtime.

At step 426, displacement-based control system 132 controls the pulsingof the beam source(s) based on the number of intrinsic skin features 70identified at step 424. For example, in some embodiments,displacement-based control system 132 initiates a second pulse of thebeam source(s) upon identify a predetermined number of features 70 inthe skin (e.g., 5 features). Thus, in such embodiments, a relativelyconstant spacing (e.g., a spacing corresponding to 5 skin features)between successive treatment spots 62 in the glide direction can beachieved regardless of the manual glide speed. Thus, the pulse frequencymay vary dynamically as a function of the manual glide speed.

In other embodiments, device 10 (or the user) sets a defined pulsefrequency (e.g., 15 Hz), as well as a predefined minimum number ofintrinsic skin features 70 (e.g., 3 features) corresponding to a desiredminimum spacing between successive treatment spots 62 in the glidedirection (e.g., about 1 mm). Displacement-based control system 132analyzes the count of identified features 70 maintained at step 424 andthe defined pulse frequency to determine whether the providing the nextpulse according to the defined pulse frequency would violate the minimumfeature count (e.g., 3 features) between successive pulses. If not,displacement-based control system 132 allows device 10 to continuepulsing at the defined pulse frequency.

However, if so (i.e., if providing the next pulse according to thedefined pulse frequency would violate the minimum feature count),displacement-based control system 132 may control radiation source 14 todelay the next pulse at least until the minimum feature count isachieved by system 132 (thus providing a minimum spacing (e.g., about 1mm) between successive treatment spots 62), or system 132 may othercontrol radiation source 14 to prevent over-treatment (e.g., decreasingthe beam intensity, turning off radiation source 14, providing feedbackto the user, etc.)

Thus, in certain embodiment, control of device 10 (e.g., controlling thepulse timing or other aspects of treatment radiation source 14) toprovide a desired spot spacing and/or to avoid over-treatment of aparticular area is not based on any signals related to the rate, speed,or velocity of device 10 moving across the skin. As discussed above, insome embodiments device 10 is not configured for detecting or measuringany data indicative of the rate, speed, or velocity of device 10 movingacross the skin, or for determining or attempting to determine the rate,speed, or velocity of device 10 moving across the skin

Multi-Pixel Displacement Sensor

As mentioned above, in some embodiments displacement sensor 100 is amulti-pixel displacement sensor 100 that employs two pixels (i.e., tworeflected beams of light for generating two signals 360), three pixels,four pixels, or more. For example, some embodiments employ a multi-pixelimaging correlation sensor 100D, of the type used in optical mice forcomputer input, for detecting displacement along the skin.

FIG. 44 illustrates an example multi-pixel imaging correlation sensor100D, of the type used in optical mice for computer input, for detectingdisplacement along the skin, according to certain embodiments.Displacement sensor 100D may include a light source 310D, a lightdetector 312D, and a processor 334.

Light source 310D may be a light-emitting diode (LED) or any othersuitable light source, e.g., as discussed above regarding light source310A. Light source 310D may be arranged to deliver light at an obliqueangle with respect to the skin surface 32, as shown in FIG. 44.

Light detector 312D may include a molded lens optic 336 and an imagingchip 338. In some embodiments, sensor 100D is configured such that theskin is within the focal plane of molded lens optic 336, which focalplane may be located several millimeters away from the surface of moldedlens optic 336, as indicated by distance z in FIG. 44. Optionally, asystem of relay lenses may be added between detector 312D and skinsurface 32 to extend the total distance from the external focal plane todetector 312D.

Detector 312D may be configured to generate a two-dimensionalmulti-pixel “image” of the area of skin surface 32 illuminated by lightsource 310D. The image may consists of a two-dimensional array ofpixels, each pixel having a signal 360 similar to signal 360 ofsingle-pixel sensor 100A or 100B. Imaging chip 338 may be configured togenerate a digital output stream to processor 334 corresponding to themulti-pixel signal array.

Processor 334 may be configured to drive light source 310D and receiveand analyze the multi-pixel array of signals from light detector 312D.In particular, processor 334 may compare different multi-pixel imagesreceived from detector 312D (e.g., successively received images) todetermine linear displacements in one or more directions, rotationaldisplacements, and/or lateral displacements of sensor 100D across theskin surface 32.

It should be understood that although the example embodiments discussedabove may be suitable for detecting roughness-type skin features, otherembodiments of sensor 100 may detect any other types of intrinsic skinfeatures, such as pigment detection in the epidermis or epidermis/dermaljunction or vascularity patterns such as the microvasculature in theskin, for example, using similar or analogous techniques to thosediscussed above.

FIG. 45 illustrates an example method 440 for controlling device 10using displacement-based control system 132 that employs a multi-pixeldisplacement sensor 100D, while device 10 is used either in a glidingmode or a stamping mode, according to certain embodiments.

At step 442, device 10 pulses the beam source(s) of device 10, togenerate one or more treatment spots 62 on treatment area 40, asdiscussed above regarding step 402. If device 10 is being used in agliding mode, the user may glide device 10 across the skin during thefirst pulse of the beam source(s). If device 10 is being used in astamping mode, the user may hold device 10 stationary on the skin duringthe first pulse of the beam source(s).

At step 444, displacement-based control system 132 performs a firstmonitoring process to monitor and analyze the lateral displacement ofdevice 10 across the surface of the skin using multi-pixel sensor 100D.Displacement-based control system 132 analyzes signals 360 as device 10is moved across the skin (e.g., in a gliding mode, during and/or afterthe first pulse of the beam source(s); or in a stamping mode, after thefirst pulse of the beam source(s)). System 132 may begin the firstmonitoring process at the initiation or conclusion of the first pulse ofthe beam source(s) or upon any other predefined event or at anypredetermined time.

At step 446, displacement-based control system 132 controls the pulsingof the beam source(s) based on the displacement of device 10 determinedat step 444. For example, in some embodiments, displacement-basedcontrol system 132 initiates a second pulse of the beam source(s) upondetermining that device 10 has moved a particular predetermined distanceacross the skin (e.g., 3 mm), based on signals from multi-pixel sensor100D. Thus, in such embodiments, a substantially constant spacing (e.g.,3 mm) between successive treatment spots 62 in the glide direction canbe achieved regardless of the manual glide speed. Thus, the pulsefrequency may vary dynamically as a function of the manual glide speed.

In other embodiments, device 10 (or the user) sets a defined pulsefrequency (e.g., 15 Hz), as well as a predefined minimum devicedisplacement for providing a predefined minimum spacing betweensuccessive treatment spots 62 in the glide direction (e.g., 1 mm).Displacement-based control system 132 analyzes the monitoreddisplacement of device 10 determined at step 444 (based on signals frommulti-pixel sensor 100D) and the defined pulse frequency to determinewhether the providing the next pulse according to the defined pulsefrequency would violate the minimum spot spacing (e.g., 1 mm). If not,displacement-based control system 132 allows device 10 to continuepulsing at the defined pulse frequency. However, if so (i.e., ifproviding the next pulse according to the defined pulse frequency wouldviolate the minimum spot spacing), displacement-based control system 132may control radiation source 14 to delay the next pulse at least untilsystem 132 determines that the minimum device displacement has beenachieved (thus ensuring the predefined minimum spacing betweensuccessive treatment spots 62), or system 132 may other controlradiation source 14 to prevent over-treatment (e.g., decreasing the beamintensity, turning off radiation source 14, providing feedback to theuser, etc.)

Thus, in certain embodiment, control of device 10 (e.g., controlling thepulse timing or other aspects of treatment radiation source 14) toprovide a desired spot spacing and/or to avoid over-treatment of aparticular area is not based on any signals related to the rate, speed,or velocity of device 10 moving across the skin. As discussed above, insome embodiments device 10 is not configured for detecting or measuringany data indicative of the rate, speed, or velocity of device 10 movingacross the skin, or for determining or attempting to determine the rate,speed, or velocity of device 10 moving across the skin.

Roller-Type Displacement Sensor 100 or Motion/Speed Sensor 102

In some embodiments, device 10 may include one or more roller-basedsensors 118 that function as a displacement sensor 100, or dwell sensor116 or as a motion/speed sensor 102, or all. Roller-based sensor 118 maybe arranged at or near the treatment tip 42 of device 10, and mayinclude a roller 450 having a leading surface that is generally flushwith, or projects slightly forward from the leading surface of thesurrounding or adjacent portion of housing 24. In some embodiments, theleading surface of roller 450 may define a skin-contacting surface 74,which may or may not affect the distance (if any) of the treatmentwindow 44 from the skin surface, e.g., depending on the closeness of theroller 405 to the window 44 and/or the force at which device 10 ispressed against the skin by the user.

FIGS. 46A-46G illustrate some example embodiments of a roller-basedsensor 118A-118G that may be used in certain embodiments of device 10.Each embodiment includes a roller 450 coupled (e.g., mechanically,optically, magnetically, electrically, etc.) to a detection system 452configured to generate signals indicative of (a) the displacement ofdevice 10 (e.g., based on a detected amount of angular rotation ofroller 45), or (b) the manual glide speed of device 10 (e.g., based on adetected speed of rotation of roller 45), or (c) a dwell sensor (e.g.,based on rotation or not rotation), or (d) all of the above.

As device 10 is manually moved across the skin, roller 450 turns or“rolls” by a degree and at a speed corresponding to the lateraldisplacement and manual glide speed, respectively, of the devicerelative to the skin surface. Detection system 452, via its coupling orinteraction with roller 450, generates signals indicative of the lateraldisplacement and/or manual glide speed, and communicates such signals toprocessor 150, which may convert and/or process such signals todetermine the displacement and/or glide speed and/or stationary statusof device 10. The determined displacement and/or glide speed and/orstationary status of device 10 may then be used for controlling one ormore controllable operational parameters of device 10 (e.g., controloperational parameters of radiation source 14), e.g., as discussedherein.

In some embodiments, roller-based sensor 118 is configured to operate asa displacement sensor 200 for use in displacement-based control system132, and may be used for any of the displacement-based controltechniques discussed herein. In some embodiments, roller-based sensor118 measures, detects, or generates signals indicative of, thedisplacement of device 10, but does not measure, detect, or generatesignals indicative of, the manual glide speed of device 10.

In an example embodiment, roller 450 has a diameter of about 4 mm, suchthat a 29 degree rotation of roller 450 corresponds to 1 mmdisplacements of device 10 (assuming no slipping between roller 450 andskin). In some embodiments, detection system 452 may be sensitive todevice displacements to a granularity of about 1 mm.

FIG. 46A illustrates an example roller-based sensor 118A that includes abelt-driven optical-interrupt detection system 452A to generate signalsindicative of the displacement and/or glide speed of device 10.

FIGS. 46B and 46C illustrate an example roller-based sensor 118B thatincludes a detection system 452B that generates signals indicative ofthe displacement and/or glide speed of device 10 based on the flexure ofa physical arm, which causes strain across a Wheatstone bridge, thuscausing changes in resistance corresponding to device movement.

FIG. 46D illustrates an example roller-based sensor 118D that includes adetection system 452D that generates signals indicative of thedisplacement and/or glide speed of device 10 based on an interactionbetween a Hall-effect sensor and one or more magnets around theperimeter of roller 450.

FIG. 46E illustrates an example roller-based sensor 118E that includes adetection 452E to generate signals indicative of the displacement and/orglide speed of device 10 based on a measured capacitance between an“antenna” and a gear or other rotating element.

FIG. 46F illustrates an example roller-based sensor 118F that includes adetection system 452F to generate signals indicative of the displacementand/or glide speed of device 10 based on measurements of reflectedoptical radiation.

Finally, FIG. 46G illustrates an example roller-based sensor 118G thatincludes a gear-driven optical-interrupt detection system 452G togenerate signals indicative of the displacement and/or glide speed ofdevice 10.

Capacitive Sensors

One or more sensors 46 of device 10 may be, or may include, capacitivesensors. As discussed above, skin-contact sensor 104 may be a capacitivesensor, in which the signal amplitude is analyzed to determine whethersensor 104 is in contact or sufficient proximity with the skin. Inaddition, any of displacement sensor 100, motion/speed sensor 102,and/or dwell sensor 116 may be capacitive sensors, or may includecapacitive sensors in addition to other types of sensors (e.g., a sensor100, 102, or 116 may include an optical reflectance/remittance sensor inaddition to a capacitive sensor for providing the desired functionality,e.g., to provide redundancy).

A capacitive sensor in contact with the skin (e.g., a capacitive sensorlocated at the application end 42 of device 10 may generate a signal(e.g., a high-frequency signal) indicating a measure of capacitanceassociated with the contact between the sensor and the skin. Forexample, a capacitive sensor's signal may be inversely proportional tothe relative displacement between the sensor and the target surface.Because the surface of a human's skin is not perfectly smooth and/orbecause a human cannot achieve perfectly steady motion during manualmovement of device 10, static friction (stiction) between device 10 andthe skin and/or other physical principles may result in “stick-and-slip”movement of device 10 across the skin, which causes micro-displacementbetween the sensor and the skin surface. This micro-displacement due tostick-and-slip movement of device 10 may result in a translationalsignal added to the nominal steady-state capacitance signal of thesensor, to provide a total capacitance signal. The amplitude and/orother aspects of the total capacitance signal may be analyzed todetermine whether the device is moving across the skin, or dwelling atthe same location. Thus, a capacitive sensor may be used as a dwellsensor 116. Such analysis may include any suitable algorithms, e.g.,comparing the signal to one or more threshold values.

As another example, the total capacitance signal may be analyzed todetermine or estimate the speed of device 10 moving across the skin.Thus, a capacitive sensor may be used as a motion/speed sensor 102. Asanother example, the total capacitance signal may be analyzed todetermine or estimate the displacement of device 10 moving across theskin. Thus, a capacitive sensor may be used as a displacement sensor100.

Treatment Sessions

In some embodiments, control systems 18 define and control individualtreatment sessions based on one or more “treatment delimiters” such as(a) a total number of treatment spots 62 generated in the treatment area40, (b) a total amount of energy delivered to the treatment area 40, (c)a total treatment time, or any other suitable delimiter(s).

In some embodiments, treatment delimiters are specified for different“types” of treatments. Different types of treatments may include (a)treatments for different areas of the body (e.g., periorbital area,areas near the mouth, the back of the hand, the stomach, the knees,etc.), (b) different treatment energy or intensity levels (e.g., highenergy treatment, medium energy treatment, low energy treatment), (c)different treatments for different stages of a multi-session treatmentplan (e.g., a first session treatment, a mid-stage session treatment, ora final-session treatment), or any other different types of treatments.

Further, treatment delimiters may be specified for differentcombinations of treatment types. For example, different values for“total treatment spots 62 generated” may be specified for differentcombinations of treatment area and treatment energy level: (a) 4,000treatment spots 62 for high energy periorbital treatment, (b) 7,000treatment spots 62 for low energy periorbital treatment, (c) 6,000treatment spots 62 for high energy hand treatment, and (d) 10,500treatment spots 62 for low energy hand treatment.

Treatment delimiters for different treatment types (or combinations ofdifferent treatment types) may be predetermined and programmed intodevice 10, set or modified by a user via a user interface 18, determinedby device 10 based on user input, sensors (such as skin temperaturesensors), settings stored in device 10, and/or algorithms 154 stored indevice 10, or determined in any other suitable manner. In someembodiments, treatment delimiters for different treatment types aredetermined based on experimental testing and preprogrammed into device10. For example, experimental testing may determine that an appropriatetreatment session for a periorbital region involves 1,000 treatmentspots 62, an appropriate treatment session for a mouth region involves1,300 treatment spots 62, and an appropriate treatment session for theback of the hand involves 2,700 treatment spots 62. These treatmentdelimiters may be stored in device 10 and implemented by control systems18 as appropriate when a user selects from a “periorbital treatment,”“mouth treatment,” or “hand treatment” via user interface 18.

Where treatment sessions are defined by treatment delimiters that arenot time-based, such as treatment sessions defined by (a) a total numberof treatment spots 62 or (b) a total amount of energy delivered to thetarget, the manual glide speed of device 10 across the skin—with thepossible exception of extremely fast glide speeds—may be largely orsubstantially irrelevant to the effectiveness of the treatment deliveredduring the session, at least in certain embodiments or configurations ofdevice 10. For example, the manual glide speed may influence the numberof times device 10 must be glided across the treatment area 40 tocomplete the treatment session (e.g., the faster the manual glide speed,the more glides are required to complete the session), but does notaffect the specified treatment delimiter for the session, e.g., thetotal number of treatment spots 62 or the total amount of energydelivered to the treatment area 40.

Further, in some embodiments, the effectiveness of the treatment, asrelated to the spacing between treatment spots 62, is generally notaffected by the manual glide speed of device 10. In embodiments thatinclude displacement-based control system 132, which controls beamdelivery, and thus treatment spot 62 generation, based on the determineddisplacement of device 10 across the skin, system 132 ensures at least aminimum spacing between successively delivered treatment spots 62, whichreduces or substantially eliminates the chances of over-irradiation ofany area. In particular, displacement-based control system 132 mayensure at least a minimum spacing between successively deliveredtreatment spots 62 during slow glide speeds, and without detecting ordetermining the manual glide speed. Thus, displacement-based controlsystem 132 may reduce or substantially eliminate the chances ofover-irradiation of any particular area, even for very slow glidespeeds.

Further, where the treatment session involves multiple glides of device10 across the treatment areas 40, the treatment spots 62 generatedduring different glides typically will not align with other, whichgenerally results in an treatment spot 62 pattern with sufficient ordesirable randomness and/or density uniformity to provide the desiredtreatment effects, without significantly over-irradiating any areas.Thus, although rapid glide speeds may require the user to perform moreglides to reach the relevant treatment delimiter (e.g., total treatmentspots 62 generated or total energy delivered), rapid glide speeds mayprovide a sufficient or desirable treatment spot 62 patterns, withoutover-irradiating any areas.

It should be noted that the manual glide speed may influence the shapeof individual treatment spots 62, e.g., the extent of elongation,“blurring,” or “smearing” of treatment spots 62, such as describedabove. Thus, operational aspects of device 10 may be configured suchthat within a reasonable range of glide speeds (i.e., less than veryfast glide speeds), the elongation or smearing of treatment spots 62does not substantially affect the physiological effectiveness of thetreatment spots 62. In some embodiments or configurations of device 10,at very high glide speeds, the elongation or smearing of treatment spots62 may significantly reduce the effectiveness of the treatment. Forexample, the energy density within a very elongated treatment spot 62may be too low to provide the intended effects. Thus, the user may beprovided general guidance (e.g., via display 32 or in a user manual)regarding the appropriate manual glide speed for the desired treatmenteffects. For example, the user may be instructed to glide device 10across the treatment area 40 at manual glide speed of roughly threeseconds per glide. The device may be configured to provide effectivetherapy at substantially all practical, or common, glide speeds used byconsumers, so that therapy is substantially independent of glide speed.

FIG. 47 illustrates an example method 460 for executing a treatmentsession for providing treatment (e.g., fractional light treatment) to auser with device 10. At step 462, one or more delimiters for a treatmentsession to be performed are determined in any suitable manner, e.g., asdiscussed above. For the purposes of this discussion it is assumed thata single treatment delimiter is determined. For example, control systems18 may determine a predefined total number of treatment spots 62 for thetreatment session based on a treatment area (e.g., periorbital area)selected by the user via a user interface 18: for example, 1200treatment spots 62. (The number of treatment spots 62 may be assumedhere to be equal to the number of beams 60 output by device 10).

At step 464, after the user has positioned device 10 against thetreatment area 40, device 10 may begin the treatment session. Inparticular, control systems 18 may deliver manually scanned arrays(e.g., rows) of beams to the treatment area 40, thus generating an arrayof treatment spots 62, as indicated at step 466. If device is operatingin a gliding mode, device 10 may glided across the skin continuouslyduring the beam-delivery process. If device is operating in a stampingmode, device 10 may held in place during each pulse, and then moved, orglided, across the surface of skin to the next treatment location forthe next pulse. The user may be instructed (e.g., by audible or visiblenotifications) when each pulse is delivered, and/or whether or whendevice 10 has been moved a sufficient distance for initiating the nextpulse (as determined by displacement monitoring and control system 132).In either the gliding mode or the stamping mode, the user may glide ormove the device across the treatment area 40 any number of times and anynumber of directions or patterns (e.g., to “paint” a two-dimensionaltarget area) during the treatment session.

During the treatment session, as indicated as step 468, displacementmonitoring and control system 132 may monitor the lateral displacementof device as it moves across the skin and control the delivery ofbeams/generation of treatment spots 62 accordingly, as discussed above.For example, system 132 may ensure that consecutive rows of treatmentspots 62 are spaced apart in the glide direction by at least a minimumdistance.

Also during the treatment session, control systems 18 may monitor thetreatment delimiter determined at step 462, as indicated at step 470.For example, control systems 18 may maintain a running count of thenumber of treatment spots 62 generated during the treatment session.Steps 468 and 470 may be performed concurrently throughout the durationof the treatment session.

At step 472, control systems 18 determines whether the treatmentdelimiter has reached the predetermined limit. For example, controlsystems 18 may determine whether the number of treatment spots 62 thathave been generated during the session has reached the predefined numberof treatment spots 62 determined at step 462 (e.g., 1200 treatment spots62). If so, the treatment session is completed at step 474. For example,control systems 18 may turn off treatment radiation source 14. If not,steps 466-472 are continued until the treatment delimiter is reached.

In some embodiments, a treatment session for providing treatment (e.g.,fractional light treatment) to a user may be completed according tomethod 460 without regard to the manual glide speed of device 10 acrossthe skin, e.g., as discussed above.

Eye Safety Sensor

In some embodiments, device 10 includes an optical eye safety sensor 114configured to detect the presence of a cornea (or other eye tissue orfeature) near a treatment output aperture of device 10, in order to helpprevent unintended eye exposure to light from the treatment radiationsource 14. For example, optical eye safety sensor 114 may be configuredto distinguish between the presence of skin and the cornea, and enabledevice 10 to treat only the intended treatment area 40. Eye safetysensor 114 may be especially important for infrared treatment light ofwavelength greater than 1400-nm, for which the eye injury risk isprimarily in the cornea or for UV, visible, and/or near-IR where retinalhazards exist. In some embodiments, optical eye safety sensor 114 isrelatively low cost, compact, easily packaged within a handheldenclosure (e.g., small and lightweight), and assembled from commonlyavailable parts. Another example embodiment of an eye safety sensor isan imaging sensor with pattern recognition for shape, color, or otherfeature of the eye.

FIG. 48 illustrates an example optical eye safety sensor 114, accordingto certain embodiments. Optical eye safety sensor 114 may include alight source 510, a light detector 512, detector optics 520, relayoptics 522 (in some embodiments), and a microcontroller 530.

Light source 510 may be a light-emitting diode (LED) or any othersuitable light source. Light source 510 may be selected for showing finedetails in the surface of human skin. Thus, a wavelength may be selectedthat penetrates a relatively shallow depth into the skin before beingreflected. For example, light source 510A may be a blue LED having awavelength of about 560 nm, or a red LED having a wavelength of about660 nm, or an infrared LED having a wavelength of about 940 nm. Red orinfrared wavelength LEDs are relatively inexpensive and work well inpractice. Alternatively, a semiconductor laser could be used.

Light detector 512 may be a photodiode, phototransistor, or other lightdetector. In some embodiments, a phototransistor has sufficient currentgain to provide a directly usable signal, without requiring additionalamplification. Light detector optics 520, e.g., a half-ball lens, may becoupled to or carried with light detector 512. Light detector optics 520may be configured to allow light detector 512 to “view” a target surfacelocation.

Further, in some embodiments, sensor 114 may include relay optics 522for relaying light from light source 510 and/or relay optics 522 forrelaying reflected light to detector 512. Relay optics 522 may be usedto relay light for any desired distance, such that one, some, or all oflight source 510, detector optics 520, and/or detector 512 may belocated at any desired distance from an aperture 526 in housing 24 thatmay be configured to be positioned on or near the skin surface 32 duringuse. Also, microcontroller 530 and/or other electronics associated withsensor 114 may be located at any distance from aperture 526 and/or fromthe other components of sensor 114 (e.g., light source 510, detector512, detector optics 520, and optional relay optics 522). In someembodiments, locating components of sensor 114 away from aperture 526may reduce or minimize the space occupied by sensor 114 at treatment tip42 of device 10, which may allow for a reduced or minimized size oftreatment tip 42, which may be desirable or advantageous.

In other embodiments, components of sensor 114 may be located nearaperture 526 (e.g., in the treatment tip 42 of device 10), such thatrelay optics 520 are not included.

Light source 510 may be oriented to illuminate a surface (e.g., skinsurface 32) at a very low angle of incidence (e.g., 0 shown in FIG. 49may be between about 5 and 40 degrees), while detector 512 may bealigned at a normal or near-normal angle of incidence relative to theilluminated surface.

Microcontroller 530 may be configured to drive light source 510 (e.g.,an LED) with a direct or modulated current, record a signal 524 fromdetector 512 using an integrated ADC 532, and analyzes the amplitude ofthe recorded detector signal 524 to determine if the surface belowdetector 512 is skin 32 or cornea 500.

The signal 524 from detector 512 may be referred to as a “reflectancefeedback signal.” The amplitude of the reflectance feedback signal 524corresponds to the intensity of reflected light from light source 510received by detector 512: the more light from light source 510 that isreflected into detector 512, the higher the amplitude of reflectancefeedback signal 524. As discussed below, due to the configuration oflight source 510 and detector 512, skin (which is relatively diffuse)reflects more of light from light source 510 into detector 512 than thecornea (which is relatively specular). Thus, microcontroller 530 mayanalyze the amplitude of reflectance feedback signal 524 (e.g., usingthreshold or window comparisons) to determine whether the surface belowdetector 512 is skin 32 or cornea 500.

Signals from microcontroller 530 indicating whether a treatment window44 of device is located above skin or the cornea may be used by controlsystems 18 for controlling one or more controllable operationalparameters of device 10.

For example, treatment (e.g., delivery of radiation to a treatment area40) may be initiated, such as to begin a treatment session, orre-initiated after an interruption during a treatment session ifmicrocontroller 530 detects a “skin presence,” e.g., by determining thatreflectance feedback signal 524 is above a predefined skin/corneathreshold or within a predefined reflectance window corresponding withskin. In such situation, control systems 18 may enable or power ontreatment radiation source 14 (or control other aspects of device 10) tobegin radiation delivery to the treatment area 40. The treatment maycontinue as long as microcontroller 530 continues to detect a skinpresence. The treatment may be interrupted upon detection of a “possiblecornea presence” or upon other treatment interrupting events.

If microcontroller 530 determines that reflectance feedback signal 524is below the predefined skin/cornea or outside the reflectance windowcorresponding with skin, microcontroller 530 may detect a “possiblecornea presence” (which is essentially a detection of a non-skinsurface, which could be a cornea, other non-diffuse surface, or lack ofa target surface, for example). Control systems 18 may disable treatmentradiation source 14 (or control other aspects of device 10) in responseto a possible cornea presence detected by microcontroller 530, in orderto prevent a possible unintended eye exposure (and possible eye damage).

The operation of sensor 114 is described below with reference to FIGS.49-50B. FIG. 49 illustrates light source 510 and two different positionsof detector 512. FIGS. 50A and 50B illustrate the local surface normaldirections for example corneas of different shapes.

Detector 512 receives a larger amount of reflected light (and thusgenerates a larger amplitude of signal 524) from diffuse surfacematerials, due to light scattering, than from smoother, more specularreflection materials. Skin is relatively diffuse, while the cornealsurface is generally smooth and specular, such that the corneal surfacehas a much lower diffuse component of reflection than the skin. Thisdifference can be used to determine whether detector 512 is positionedover an area of skin 32 or over the cornea 500.

This technique of discriminating between diffuse and specular materialsusing a single beam source 510 and single detector 512 may assume thatthe angles between the target surface normal and both the beam source510 and detector 512 are known at least to an extent. In particular, theangles at which beam source 510 and detector 512 are aligned relative tothe target surface may be selected such that the reflectance feedbacksignal 524 can be reliably used to distinguish reflection off the skinfrom reflection off the cornea, for a known range of corneal curvatures,as discussed below with respect to FIGS. 50A and 50B.

In general, the local surface normal vector of a surface (e.g., skin orcorneal surface) will vary relative to a larger-scale average surfacenormal, depending on the local curvature of the surface. For example,near the edge of the cornea, the local surface normal will be at leastseveral degrees offset from the normal vector at the center of thecornea, because the cornea is a curved surface.

Assume a light beam source illuminates a surface at an incidence ofnear-grazing (˜0 degrees) and a detector views this surface at nearnormal incidence (˜90 degrees). For less curved surfaces, the localsurface normals are relatively close to 90 degrees, as shown in FIG. 50.In an extreme case shown in FIG. 50B, in which curvature provides alocal surface normal of 45 degrees, a specular reflection propagatesdirectly into the detector. It may be assumed for the purposes of sensor114 that the exposed corneal surface forms an angle of less than 45degrees with the larger surface normal of the face (i.e., skin adjacentthe eye), such that a direct specular reflection from beam source todetector does not occur for any practical configuration of sensor114/device 10 relative to the face. It is also known that for a normaleye, the most extreme angle near the corneal edge is less than 40degrees. (See, e.g., James D. Doss, “Method for Calculation of CornealProfile and Power Distribution”, Arch Ophthalmol, Vol. 99, July 1981).Moreover, this angle quickly decreases to near 20 degrees within 60% ofthe central cornea region, i.e., the curvature is not large near thecornea center. Therefore, for the central 60% cornea region, thespecular reflection from the cornea will not be intercepted by thedetector with a large margin.

Thus, assuming light source 510 is arranged at a sufficiently low angleof incidence (e.g., θ shown in FIG. 49 between about 5 and 40 degrees),for all practical cases the cornea will not reflect the light from lightsource 510 directly into detector 512. Thus, for all practical cases,the cornea will reflect less light from light source 510 into detector512 than will the skin. Thus, for practical cases, the cornea can bedistinguished from skin, assuming the proper signal amplitude thresholdsare utilized by microcontroller 530. Thus, to summarize, assuming theproper orientation of light source 510 and detector 512, as well as theproper selection of threshold(s) for comparing the amplitude ofreflectance feedback signal 524, sensor 114 is able to reliablydiscriminate between the skin and the cornea, especially for the centralcornea region which may be the most important for vision.

It has been shown experimentally that the scattering coefficient of skindermis μm_(s) _(—) _(skin) is substantially greater than that of thecornea μm_(s) _(—) _(cornea). In particular, the scattering coefficientof skin dermis μm_(s) _(—) _(skin)≈60 cm⁻¹ for 500-nm wavelength (seeSteven L. Jacques, “Skin Optics”, Oregon Medical Laser Center News,January 1998), whereas the scattering coefficient of skin dermis μm_(s)_(—) _(cornea)≈10 cm⁻¹ for 500-nm wavelength (see Dhiraj K. Sardar,“Optical absorption and scattering of bovine cornea, lens, and retina inthe visible region”, Laser Med. Sci., 24(6), November 2009). Based onthese respective scattering coefficients, the expected diffusedreflectance of the cornea is about 8%, while the expected diffusedreflectance for a typical Fitzpatrick Type I to VI skin ranges from 70%to 10% respectively. Thus, for most skin types, the reflectance contrastis large enough discriminating thee cornea from the skin, again assumingthe proper comparison thresholds or windows are utilized by sensor 114.

Multi-Sensor Eye Safety System

In some embodiments, device 10 includes a multi-sensor control/safetysystem that includes one or more eye safety sensor 114 and one or moreskin contact sensors 104.

FIG. 51 illustrates an example multi-sensor control/safety system 550that includes one or more eye safety sensor 114 and one or more skincontact sensors 104 arranged on or near device application end 42.System 550 combines the functionality of eye safety sensor 114 and skincontact sensor(s) 104 to provide more reliable and/or redundant eyesafety functionality as compared to eye safety sensor 114 or skincontact sensor(s) 104 acting alone.

System 550 may configured to control device 10 (e.g., turn treatmentradiation source 14 on/off) based on independent determinations made byeye safety sensor 114 and skin contact sensor(s) 104, in any suitablemanner. The independent determinations made by eye safety sensor 114 andskin contact sensor(s) 104 may be based on comparisons of signalsdetected by such sensors to respective thresholds, referred to herein as“independent determination thresholds.”

For example, system 550 may trigger a control signal to turn ontreatment radiation source 14 if either (a) eye safety sensor 114determines a “skin presence” (discussed above), independent of anydeterminations or signal analysis by contact sensor(s) 104, or (b) allcontact sensors 104 determine a contact status with the skin,independent of any determinations or signal analysis by eye safetysensor 114. Thus, system 550 may trigger a control signal to turn offtreatment radiation source 14 only if both (a) eye safety sensor 114determines a “possible cornea presence” (discussed above), independentof any determinations or signal analysis by contact sensor(s) 104, and(b) at least one contact sensor 104 determines a non-contact status withthe skin, independent of any determinations or signal analysis by eyesafety sensor 114.

Alternatively, system 550 may trigger a control signal to turn ontreatment radiation source 14 only if both (a) eye safety sensor 114determines a skin presence (discussed above), independent of anydeterminations or signal analysis by contact sensor(s) 104, and (b) allcontact sensors 104 determine a contact status with the skin,independent of any determinations or signal analysis by eye safetysensor 114. Thus, system 550 may trigger a control signal to turn offtreatment radiation source 14 if either (a) eye safety sensor 114determines a possible cornea presence, independent of any determinationsor signal analysis by contact sensor(s) 104, or (b) any contact sensor104 determines a non-contact status with the skin, independent of anydeterminations or signal analysis by eye safety sensor 114.

Alternatively or in addition, system 550 may be configured to controldevice 10 (e.g., turn treatment radiation source 14 on or off) based oninter-dependent analysis of signals from eye safety sensor 114 andsignals from skin contact sensor(s) 104. For example, system 550 mayutilize algorithms that analyze signals detected by eye safety sensor114 (e.g., reflectance feedback signal 524 from detector 512) andsignals detected by contact sensor(s) 104 (e.g., signal 552 detected bycontact sensor(s) 104) to determine whether to trigger a particularcontrol signal. For example, such algorithms may incorporate thresholdsthat are lower than the independent determination thresholds discussedabove. Such thresholds are referred to herein as “inter-dependent sensoranalysis thresholds.”

To illustrate by example, system 550 may specify the followingindependent determination thresholds:

-   -   (a) 10 mV eye safety threshold: eye safety sensor 114 determines        a possible cornea presence if the amplitude of reflectance        feedback signal 524 falls below 10 mV, and    -   (b) 50 pF contact sensor threshold: contact sensor 104        determines a non-contact status if the amplitude of contact        sensor signal 552 falls below 50 pF.

Further, system 550 may specify the following inter-dependent sensoranalysis thresholds:

-   -   (a) 15 mV eye safety threshold for reflectance feedback signal        524, and    -   (b) 70 pF contact sensor threshold for signal 552.

System 550 may utilize an algorithm 154 that incorporates theinter-dependent sensor analysis thresholds (15 mV and 70 pF). Forexample, an algorithm may specify a control signal to turn off treatmentradiation source 14 if both (a) reflectance feedback signal 524 fallsbelow 15 mV and (b) contact sensor signal 552 falls below 70 pF.

As another example of controlling device 10 based on inter-dependentanalysis of signals from eye safety sensor 114 and signals from skincontact sensor(s) 552, an algorithm 154 may calculate an index, referredto herein as an “eye safety factor index,” or ESF index from reflectancefeedback signal 524 and contact sensor signal 552. The algorithm mayweight reflectance feedback signal 524 and contact sensor signal 552 inany suitable manner. An example algorithm is provided as equation (1):

ESF index=signal 524 amplitude*W1+signal 552 amplitude*W2  (1)

-   -   where W1 and W2 represent any suitable constants (including 0).        Another example algorithm is provided as equation (2):

ESF index=(signal 524 amplitude+C1)*(signal 552 amplitude+C2)  (2)

-   -   where C1 and C2 represent any suitable constants (including 0).

Any other suitable algorithms may be used for calculating an ESF indexbased on reflectance feedback signal 524 and contact sensor signal 552.

ESF index may then be compared to a predefined threshold to determinewhether to trigger a particular control signal (e.g., to turn offtreatment radiation source 14), or compared to multiple differentpredefined thresholds for triggering different control signals. Suchalgorithms (using the same or different threshold values) may be usedfor triggering any suitable control signals, such as control signals forturning on treatment radiation source 14, turning on treatment radiationsource 14, changing the current treatment mode, or adjusting anycontrollable operational parameter of device 10.

FIG. 52 illustrates an example method 600 for controlling device 10(e.g., controlling treatment radiation source 14) using a multi-sensorcontrol/safety system 550, according to certain embodiments. At step602, a user prepares for a treatment session by selecting a treatmentmode and/or other treatment parameters, and places the application end42 of device 10 against the skin.

At step 604, system 550 determines whether the application end 42 iscorrectly positioned against the skin for treatment, e.g., using any ofthe techniques discussed above or any other suitable technique.

If system 550 determines that the application end 42 is correctlypositioned against the skin for treatment, system 550 may generate acontrol signal for beginning a treatment session automatically or upon adefined user input (e.g., pressing a treatment button), as indicated atstep 606. Control systems 18 may also generate feedback to the userindicating that treatment has been initiated or that treatment is readyfor initiation upon the defined user input (e.g., pressing a treatmentbutton).

Device 10 may then activate radiation source(s) 14 to deliver beams 60to the treatment area 40 to generate treatment spots 62, as indicated atstep 608. The user may operate device 10 in a gliding mode or a stampingmode, depending on the configuration and/or selected treatment mode ofdevice 10.

During the treatment, system 550 continually or repeatedly determineswhether the application end 42 is still correctly positioned against theskin for treatment, as indicated at step 610. As long as system 550determines that application end 42 is correctly positioned against theskin for treatment, system 550 may continue to generate control signalsfor continuing the treatment session (i.e., such that control systems 18continues to provide beams 60 to generated treatment spots 62 intreatment area 40), as indicated at step 612.

However, during the treatment, if system 550 determines that applicationend 42 is not correctly positioned against the skin for treatment (e.g.,if system 550 determines that application end 42 is located over thecornea or moved out of contact with the skin), system 550 may generate acontrol signal for automatically stopping or interrupting the treatmentsession, e.g., by turning off or disabling treatment radiation source14), as indicated at step 614. Control systems 18 may also generatefeedback, e.g., audible or visual feedback, to the user indicating thestatus of device 10. For example, control systems 18 may provide generalfeedback indicating that the treatment has been stopped or interrupted,or may provide more specific feedback indicating the reason that thetreatment has been stopped or interrupted, such as feedbackdistinguishing between eye detection, non-contact detection, and devicemalfunction, for example.

System 550 may continue to monitor the positioning of application end 42at step 616. If system 550 determines that application end 42 has againbecome correctly positioned against the skin for treatment, system 550may resume the treatment session, e.g., by generating a control signalto resume treatment (e.g., by turning on treatment radiation source 14),as indicated at step 618, and resuming the generation of treatment spots62 in the skin, as indicated by the method returning to step 608.

The treatment session may end upon reaching a treatment delimiter (suchas discussed above regarding FIG. 48), or after a predefined time, orbased on any other parameters defining the treatment session. It shouldbe understood that this example and FIG. 52 can apply to sensors otherthan contact sensor in a similar manner.

Calibration of Eye Safety Sensor

In some embodiments, eye safety sensor 114 can be individuallycalibrated to the current user of device 10. FIG. 53 illustrates anexample method 650 for calibrating eye safety sensor 114 for one ormultiple users. A calibration process is performed at steps 652-660. Atstep 652, a user positions the application end 42 of device 10 againstthe user's skin, e.g., upon instruction from device 10. Device 10 mayinstruct the user to position application end 42 against a certain partof the body, e.g., the face or back of the hand. Sensor 114 is activatedand records a reflectance/remittance feedback signal 524 at step 654. Atstep 656, the user may move the application end 42 of device 10 acrossthe skin, e.g., upon instruction from device 10. Sensor 114 may continueto record reflectance feedback signal 524 at various locations ofapplication end 42 on the skin, at step 658.

At step 660, microcontroller 530 may analyze signal 524 recorded atsteps 654, 658 to calibrate sensor 114. For example, microcontroller 530may execute one or more algorithms to determine one or more appropriatethreshold values (e.g., threshold voltages) for distinguishing betweenskin and the cornea, e.g., for determining a “skin presence” or“possible cornea presence,” as discussed above. Such threshold valuesmay be stored by sensor 114 or control systems 18.

At step 662, the same user or a different user may initiate device 10for a treatment session. The user may identify him or herself via a userinterface 18, e.g., by scrolling and selecting from a list of names, orentering a new name, at step 664. Device 10 may then determine whethereye safety sensor 114 has been calibrated for that user, and if so,access the skin/cornea determination thresholds stored for that user, atstep 666. If the user is a new user or eye safety sensor 114 has notbeen calibrated for that user, device 10 may calibrate sensor 114 forthat user to determine and store skin/cornea determination thresholdsfor that user, at step 668 (e.g., by leading the user through thecalibration process of steps 652-660).

After the skin/cornea determination thresholds for the user have beenaccessed (or in the case of a new user, determined and stored), the usermay select various operational parameters and begin a treatment sessionusing device 10. During the treatment session, at step 670, eye safetysensor 114 may continually or repeatedly monitor the surface underapplication end 42 using the user-specific thresholds accessed at step666 or 668.

In other embodiments, device 10 may require eye safety sensor 114 to berecalibrated before each treatment session.

Dual-Function Sensors

In some embodiments, in addition to providing eye safety functionality,eye safety sensor 114 may also be used as a displacement sensor,operating in a similar manner as discussed above regarding single-pixeldisplacement sensor 100A, 100B, or 100C shown in FIGS. 37-39. Forexample, the functionality of eye safety sensor 114 and displacementsensor 100A/100B/100C may be integrated into a single sensor 100/114.Thus, a single light source and single detector may be used to provideboth the eye safety and displacement monitoring functions describedabove. The integrated displacement/eye safety sensor 100/114 includesone or more microcontrollers or other processors for providing thefunctionality of both sensors.

In other embodiments, device 10 may include both eye safety sensor 114and one or more displacement sensors 100 (e.g., one or more single-pixeldisplacement sensors 100A/100B/100C and/or one or more multi-pixeldisplacement sensors 100D), wherein eye safety sensor 114 provides (inaddition to its eye safety functionality) device displacement monitoringfunctionality to supplement or provide a backup to the displacementsensor(s) 100A/100B/100C.

Additional Embodiments and Features

Another example embodiment of device 10 is shown in FIGS. 54 and 55, anddiscussed below.

FIG. 54 shows an embodiment of device 10 that may be approximately 12 cmlong, having a generally rectangular cross-section in the upper portionof approximately 2 cm×4 cm, and a nearly square cross-section in thelower portion of about 2 cm×2 cm. These dimensions and shapes areexemplary only, to give a sense of the scale of the device and itscomfort as a hand-held device, and such dimensions and shapes are notintended to be limiting in any manner.

The upper portion of housing 24 may house, for example, two AA-sizelithium polymer batteries 20, and user interfaces 28 including an on/offbutton 200 and operational indicator 54 such as an LED, as well as acharger port 174 for recharging the batteries 20. The middle region ofthe device may house control electronics 30 for controlling theenergizing of a laser 14 (which may include, e.g., between one and fouredge emitting laser diodes, which are referred to hereinafter simply aslaser 14 for clarity) and responsive to a contact sensor 104 and eithera displacement sensor 100 or a motion/speed sensor 102, depending on theparticular embodiment. This location of electronics 30 allows for theelectronics 30 to be thermally coupled to a heat sink 36, in this case athermal mass (for example, a cylinder of copper) located in the lowerportion of the device.

In an embodiment, to prevent the laser 14 from overheating, the lasermay be arranged in direct thermal contact with the thermal mass heatsink 36. During operation, the waste heat from the edge emitting laserdiode 14 is conducted into the mass 36. For example, the thermal mass 36can be machined out of copper in such a way that the laser 14 is pressedinto an opening in the copper cylinder, and in some embodiments the mass36 can serve as one electrical conduit for connecting the laser drivecircuit 30 to the edge emitting laser diode 14.

The displacement sensor 102 or motion/speed sensor 102 may be locatedvery close to the treatment tip 42 of the housing 24, generally adjacentto the edge emitting laser diode 14 as shown in FIG. 54. The contactsensor 104 may also be located at or near the device tip 42, and forexample may comprise a capacitive sensor partly or wholly surrounding awindow 44 through which a laser beam or beams 60 are delivered towardthe skin 40, although mechanical sensors are also acceptable in someembodiments. The window 44 may be selected from a group comprisingsapphire, quartz, diamond, or other material transparent at thefrequency of the edge emitting laser diode and having a good thermalcoefficient. In some embodiments, the window 44 is placed in contactwith the skin surface 38 during treatment.

Referring next to FIG. 55, an example operational schematic of device 10of FIG. 54 is shown in block diagram form. At least one microprocessor150 receives power from batteries 20 or other power supply. Inembodiments in which rechargeable batteries are used, a charger circuit176 and charging port 174 may be provided, with the charging port 174also receiving control signals from processor 150 to preventovercharging and detect operational errors.

On on/off button 200 may enable operation of the circuitry, such thatwhen power is applied to the microprocessor 150, an indicator light orLED 54 is illuminated. A contact sensor 104 detects contact with auser's skin, as discussed above, while either a displacement sensor 100or a motion/speed sensor 102 detects displacement or motion of thedevice across the skin at a displacement or rate deemed sufficient toprevent multiple firings of laser 14 in too-close proximity to oneanother, thus preventing overlap of successive treatment spots 64. Thecontact sensor 104 and displacement sensor 100 or motion/speed sensor102 may provide input to the processor 150, which allows the processorto energize a laser drive circuit 30 safely and effectively. Whenpermitted by the processor 150, the laser drive circuit 30 energizesedge emitting laser diode 14, which causes a pulsed beam 60 to beemitted through the outlet window 44 described above.

In one embodiment, the non-ablative fractional device 10 mayincorporate, for example, a mid-infrared edge emitting laser diode inthe wavelength range of 1.4-1.6 microns, such as those available fromSemiNex Corporation (Peabody, Mass.). These very small (4 mm×7 mm×8 mm)laser devices produce about 6 watts of laser power. Device 10 may set apulse duration of about 5 ms, which may produce about 30 mJ of energyper pulse. The laser can operate at a pulse repetition rate of about 20Hertz, for example. According to these example parameters, the diodevoltage may be about 1.7 volts at a current of about 10 amperes,resulting in an efficiency of about 35%. The output wavelength may be,for example, 1.47 microns (SemiNex Part No. C-1470-6-95).

Beam propagation according to such embodiments may be simpler and morereliable than in conventional devices. As described above, the directlaser output of a typical diode laser is highly divergent in the fastaxis, with considerably lower divergence in the slow axis. In certainconventional devices, a cylindrical microlens or other optic may beplaced in the optical path, very close to the emitter surface (or“facet”), to collimate or reduce the divergence of the beam in the fastaxis. Further in the optical path, a second cylindrical lens or otheroptic may be positioned orthogonal to the first lens, to collimate orreduce the divergence of the beam in the slow axis. This relativelycomplex arrangement is used in certain conventional devices because itallows the beam to be propagated through various beam-scanning optics.However, in such conventional devices, careful and laborious (andcostly) positioning of the lenses or other optics may be necessary tobring the beam to focus on the skin at the output window, wherein theemitter facet is approximately 1 micron by 100 microns, and the exitwindow has an area of one square centimeter or more.

In contrast, certain embodiments disclosed herein eliminate themicrolenses or other optics used in such conventional devices, andinstead locate the diode laser emitter facet (i.e., emitter surface)very close to the skin surface (e.g., with only a thin window betweenthe diode laser emitter facet and the skin, and rely on the divergenceand propagation characteristics of the unmodified beam 60 to create anappropriately sized treatment spot 62 and MTZ 64 on the skin. Forexample, a 1-micron by 95-micron beam with divergence of about 28 degFWHM by about 6 deg FWHM, respectively, may expand to an approximatelycircular beam of about 120 microns at a distance of 240 microns from theemission facet. Using an approximately 0.14 mm thick window with itsinput face about 100 microns from the emitter facet, and its output facetouching the skin at a distance of about 240 microns from the emitterfacet may produce a treatment spot 62 on the skin surface of about 120microns in diameter. With a device glide speed of about 2 cm/s and a5-ms pulse duration, the treatment spot 62 becomes an oval of about 120μm by 220 μm in diameter.

While some embodiments omit lenses of any type (as discussed above), insome embodiments device 10 may include a simple lens for beam shapingwhile still benefiting from various advantageous aspects discussedabove. For example, if a larger treatment spot 62 or MTZ 64 is desired,a diverging lens can be used; or, alternatively, the edge emitting laserdiode 14 can be moved slightly further from window 44, for example by anadditional 100 microns, allowing a longer propagation path for the beam60 before it reaches the skin. If a smaller treatment spot 62 or MTZ 64is desired, a simple converging lens can be used. Utilizing exampletreatment parameters described more fully below, the percentage of areatreated may be between about 1% and about 10%, e.g., about 5% of theskin surface if the treatment spot diameter is about 65 microns, andbetween about 10% and about 30%, e.g., about 20% of the skin surface ifthe treatment spot diameter is about 130 microns, when, for example,device 10 is used daily for about one month.

In some embodiments, and for particular operational parameters, the beammay have an elliptical shape of approximately 150 μm by 250 μm at adepth into the skin of about 260 μm, assuming the device is heldstationary on the skin. When the device is glided across the skin, thiselliptical shape becomes a roughly circular zone of about 250 μm indiameter. This re-shaping of the beam at depth occurs due to themovement of the device across the skin. In some embodiments, the usermay be instructed to move device 10 in a generally side-to-side orserpentine manner, e.g., as shown in FIG. 8C, 8D, 8F, or 8G, forexample.

The simplicity of certain embodiments disclosed herein may reduce orminimize the electrical load on the battery/batteries 20, which mayallow for sufficient charge from a single AA-sized battery. To provide apeak current requirement of, for example, 10 amps, two AA-sizedbatteries may be used in some embodiments. Operation of an exampleembodiment of device 10 at, for example, 6 watts of optical output powerfor 120 seconds may requires a charge of only 34 mAh, whereas a typicalsingle AA-sized lithium polymer battery has a charge of about 600 mAh.For example, an IMR 14500 rechargeable battery available fromwww.lighthound.com has a continuous discharge current capability of 3amps, or 6 amps for two batteries in parallel. For an example laserpulse duration of 5 ms (and an example duty cycle of about 10%), thisbattery pair can readily produce current pulses of 10 amps or more. Avery low current battery-charger port 174 may be included at the backend of device 10, as shown in FIG. 54.

Some embodiments of device 10 may include a motion/speed sensor 102comprising an accelerometer for determining motion of the device 10.However, the operation of the accelerometer in device 10 may differsignificantly from those found in the conventional devices. For aneffective operation of certain embodiments of device 10, absolutelocation relative to the prior laser pulse is not important as long asthe new location is at a location different from the prior laser pulse.Thus, in such embodiments, as long as a detectable signal from theaccelerometer confirms that device 10 is undergoing acceleration, andcontact sensor 104 confirms that device 104 is in contact with the skin40, the next laser pulse can be at any location. One example of asuitable accelerometer is the LIS305DL available from STMicroelectronics (Santa Clara, Calif.), which is a three axis linearaccelerometer measuring about 3 mm by 5 mm by 0.9 mm in size and can bereadily mounted by any conventional means at or near the tip 42 ofdevice 10 and electrically connected to processor 150. In an alternativeembodiment, the motion/speed sensor can be a vibration and tilt sensorsuch as a SignalQuest SQ-MIN-200. Other embodiments of device 10 includea displacement sensor 100 (e.g., as discussed above in greater detail)instead of a motion/speed sensor 102 or accelerometer.

To reduce or minimize the size and power consumption of device 10, someembodiments use a thermal mass 36 to mitigate temperature rise in thedevice. The mass 36 can be, for example, solid copper which has avolumetric heat capacity of 3.45 joules per centimeter cubed per degreecentigrade. For an example embodiment operating with two lithium AAbatteries operating at 3.5 V and an average current of 1A (e.g., 10A at10% duty cycle) for two minutes, the total heat generated is slightlyover 400 joules. Certain edge emitting laser diodes can operate safelywith a temperature rise of about 20° C. or more; thus the volume ofcopper required to effect a thermal mass temperature rise of 20° C. isabout 6 cubic centimeters. This corresponds to a 14 mm diameter rodabout 4 cm in length, or approximately the diameter of an AA batterywith slightly shorter length. Alternatively, the mass 36 can comprise asealed thermally conductive cylinder or other shape container filledwith a liquid such as water, or a phase change material such as a waxwith a melting point of around 30° C. In some embodiments, or for somepatients, it may be desirable to cool or chill device 10, or at leastthermal mass 36, before using device 10. For example, if mass 36comprises a sealed container filled with water, freezing the water inthe container can offer the ability to absorb substantially more energywithout any temperature increase during the melting process.

By locating the laser control electronics 30 at the opposite end of thecopper cylinder from the laser 14, the waste heat from electronics 30(included in the above total) is also deposited in the copper mass 36.Once the device thermal mass 36 has reached approximately 40 deg C. (orother predefined temperature), the microprocessor 150 may preventfurther operation of device 10 until room temperature is once againestablished in the thermal mass 36.

In a particular embodiment, device 10 may be designed to produce a 30-mJpulse in 5 ms, forming a treatment spot 62 of about 120 vim by 220 μm atthe skin surface. This energy is sufficient to produce denatured skin toa depth of at least 250 μm, which is generally comparable to certainoffice-based fractional treatment devices. An embodiment of device 10configured for non-ablative fractional treatment may be used in thefollowing manner, as an example. The on/off button 200 is pressed toturn the device on. The LED 54 is energized that is visible to the user,indicating that device 10 is ready for a treatment to be performed. Theoutput window 44 of device 10 is then touched to the skin in the area tobe treated, and device 10 is moved back and forth across the skinsurface 38 at a manual glide speed generally in the range of about 1-2cm/s, although in some applications the manual glide speed and/or thepulse repetition rate or duty cycle can vary considerably, as discussedfurther below. When contact with the skin surface 38 is verified by acontact sensor 104, and appropriate displacement or acceleration of tip42 is sensed by displacement sensor 100 or motion/speed sensor 102 oraccelerometer, pulsed laser beams 60 are emitted through the window 44to the skin, and the LED 54 on device 10 flashes synchronously with thelaser emission. If the tip 42 is (a) not moving; (b) failing to achievesufficient displacement, motion, or acceleration across the skin; (c)moving too slowly or too quickly; (d) moving but undergoing noacceleration for an embodiment with an accelerometer; or (e) not incontact with the skin, device 10 may prevent pulsing of the laser.Condition (d) may occur if device 10 is moved in a straight line for,e.g., 5-10 centimeters at constant speed. If device 10 is moved back andforth across the skin, or varies moderately from a straight line, tip 42will undergo acceleration at all times, thus enabling pulsing of thelaser.

In some embodiments or applications, a manual glide speed of about 2cm/s or 1 inch/s can be treat an area of about 20-30 cm² in a treatmentsession of about two minutes. This treatment area may be sufficient forcoverage of the two periorbital regions when used as described above. Atan example pulse repetition rate of about 10 Hz, roughly 50 MTZs arecreated in an area of roughly one square centimeter in about fiveseconds. In a month of once-daily treatments, about 1500 MTZs/cm² arecreated, which may be generally comparable to certain office-basedsystems.

After a predefined period of operation, e.g., two minutes, device 10 mayautomatically turn itself off, and may remain inoperable for somedefined time period or until certain condition(s) are present, e.g.,until the device heat sink 36 has returned to room temperature or otherselected temperature, or until the battery 20 has substantially fullyrecharged, or both. In one embodiment, a full recharge of battery 20takes approximately one hour, whereas heat sink 36 may return to roomtemperature more quickly.

In some alternative embodiments or application, device 10 can beoperated at with somewhat faster manual glide speeds and higher pulserepetition rates to allow for greater areal coverage in a particulartime period time. For example, for a pulse repetition rate of 20 Hz,operating for a period of two minutes, with a manual glide speed ofabout 2 cm/s, certain embodiments of device 10 can cover an area of40-60 cm². When applied twice daily for thirty days, e.g., the totaldensity of MTZs may be greater than or equal to the MTZ density achievedwith certain office-based fractional treatment systems in a singlemonthly treatment, for example.

If greater coverage per unit of time is desired while maintaining asufficient density of MTZs, the pulse repetition rate of the edgeemitting laser diode may be increased in some embodiments, e.g., toapproximately 30 Hz rather than 10 or 20 Hz, with a manual glide speedof about 2.5 cm/s, or about 1 inch/s. In such embodiments, approximately300 MTZs may be deposited in an area of about 6 square centimeters, orabout one square inch, for a density of about 50 MTZs/cm², but in aboutone-third the time compared to a pulse repetition rate of 10 Hz. Thismay allow treatment of each periorbital region in about 10-15 seconds,and a full face in about five minutes.

Appropriate reductions can be made for automatic turn-off time after acessation of motion; for example, within 30 ms of motion cessation for a30 Hz device, versus 100 ms for a 10 Hz device. It will be appreciatedthat the foregoing duty cycles and pulse repetition rates are examplesonly, and significant variation is permitted in other embodiments.

In at least some embodiments of device 10, eye safety is assured basedon contact sensor 104. Mid-infrared lasers are frequently referred to as“eye-safe” lasers, because light in the wavelength region of 1.4-1.6microns is absorbed in the cornea and cannot pass through the vitreoushumor of the eye. However, with sufficient fluence, one or moretreatment spots could conceivably be created on the cornea unlessappropriate safety measures are incorporated. Certain embodiments ofdevice 10 (e.g., direct exposure embodiments using an edge emittinglaser diode as the radiation source 14) utilize a rapidly divergingbeam, such that the laser fluence at the cornea surface is insufficientto cause any damage unless the treatment tip 42 of device 10 is placedwithin approximately 5 mm of the cornea. Nonetheless, to ensure safeoperation, certain embodiments include one or more contact sensors 104at the device tip 42, which is/are connected to processor 150, to enablelaser emission only when device tip 42 is in contact with the skin.Thus, for certain embodiments of device 10, the risk of eye injury maybe substantially eliminated unless device 10 was placed directly on theeyeball, and then moved along the eyeball surface while maintainingcontact. Other embodiments may alternatively, or in addition, include aneye safety sensor 114, e.g., as described above regarding FIGS. 48-51,which may further improve the eye safety aspect of device 10.

In some embodiments, e.g., where device 10 is configured for providingnon-ablative fractional treatment, the operation of device 10 may allowfor the introduction of topical agents through the stratum corneum andepidermis without providing an easy path by which undesirable bacteriacan enter the body. It is well known that the uppermost layers of skin,namely the stratum corneum at the very top and epidermis immediatelyunderneath, provide a strong and important “wall” protecting theunderlying dermis and the blood vessels contained therein from theoutside world. In particular, these upper layers greatly impede theability of bacteria to reach the dermis, which if allowed in couldpotentially infect the entire body through the blood supply.

This same “wall,” however, also impedes or prevents various desirabletopical agents, such as anesthetics, moisturizers, wrinkle reducers(whether of the neurotoxin type such as Botox, or collagen growthstimulating serums, etc.) and similar agents from reaching the dermisand achieving the desired benefit.

Various known methods exist for mechanically breaching this barrier. Forexample, rollers with dozens or hundreds of very fine needles have beenemployed, with the needles of perhaps 200 microns or more in length, tobreak through to the dermis; and more recently, laser-drilledmicro-holes of perhaps 100 microns in diameter and up to a millimeter ormore in depth have been successfully created using so-called fractionalablative lasers. However, while the holes created by these prior arttechniques facilitate transport of a topical into the dermis, they alsoprovide a ready path for bacteria to invade the body.

In contrast, the creation of microthermal zones of denatured skin usingcertain embodiments of device 10 may provide a reasonable compromisebetween increasing transport of a variety of topical agents into thedermis while still providing a barrier to bacteria. The column ofdenatured skin formed by a microthermal zone 64 has increasedpermeability to surface-applied agents, and thus allows an increasedconcentration of an applied topical to reach the dermis. At the sametime, the denatured skin of the MTZ 64 may continue to provide aphysical barrier to bacteria.

1. A self-contained, hand-held device for providing a dermatologicaltreatment, the device comprising: a device body configured to behandheld by a user; a radiation source supported in the device body, theradiation source including a beam source configured to generate anenergy beam; an application end configured to be manually moved acrossthe surface of the skin during a treatment session; electronicsconfigured to pulse the radiation source during the treatment sessionsuch that the beam source emits pulsed energy beams to the skin; and adisplacement control system including: a displacement sensor configuredto determine a displacement of the device relative to the skin; andelectronics configured to control at least one operational parameter ofthe device based on the determined displacement of the device relativeto the skin.
 2. The device of claim 1, comprising electronics configuredto control at least one operational parameter of the radiation sourcebased at least on the determined displacement of the device relative tothe skin.
 3. The device of claim 2, comprising electronics configured tocontrol a pulse frequency rate of the radiation source based at least onthe determined displacement of the device relative to the skin.
 4. Thedevice of claim 2, comprising electronics configured to control a pulseduration based at least on the determined displacement of the devicerelative to the skin.
 5. The device of claim 2, comprising electronicsconfigured to stop of delay pulsing of the radiation source based atleast on the determined displacement of the device relative to the skin.6. The device of claim 1, wherein each pulsed energy beam emitted by thepulsed beam source has the same, fixed propagation path with respect tothe device body.
 7. The device of claim 1, wherein the displacementcontrol system is programmed to prevent or reduce the likelihood ofover-treatment of a location on the skin.
 8. The device of claim 1,wherein the displacement control system is programmed to prevent orreduce the likelihood of treatment spots overlapping each other.
 9. Thedevice of claim 1, wherein the displacement control system is programmedto provide a defined minimum spacing between adjacent treatment spots.10. The device of claim 1, wherein the displacement control system isconfigured to: analyze signals from the displacement sensor to identifyskin features in the skin; count the number of identified skin features;and control one or more operational aspects of the device based on thecounted number of identified skin features.
 11. The device of claim 10,wherein the displacement control system is configured to control theradiation source based on the counted number of identified skinfeatures.
 12. The device of claim 10, wherein the displacement controlsystem is configured to enable the radiation source only if the countednumber of identified skin features reaches a predetermined minimumnumber of skin features.
 13. The device of claim 1, wherein the devicedoes not detect or determine a speed of movement of the device.
 14. Thedevice of claim 1, wherein the displacement sensor includes aroller-based sensor.
 15. The device of claim 1, wherein the displacementsensor is a single-pixel displacement sensor.
 16. The device of claim15, wherein the single-pixel displacement sensor is lensless.
 17. Thedevice of claim 15, wherein the single-pixel displacement sensorincludes: a light emitter configured to deliver light toward the skin; alight detector configured to detect light reflected and/or remitted fromthe skin, and generate a signal; and control electronics for analyzing asignal from the detector.
 18. The device of claim 1, wherein thedisplacement sensor is a multi-pixel imaging displacement sensor. 19.The device of claim 18, wherein the displacement sensor is a mouse-typetwo-dimensional imaging sensor.
 20. The device of claim 1, furtherincluding a control system for: determining a delimiting value of adelimiting parameter for a treatment session; monitoring the delimitingparameter during the treatment session; and automatically terminatingthe treatment session upon reaching the delimiting value of thedelimiting parameter.
 21. The device of claim 20, wherein the delimitingparameter comprises a total number of treatment spots for the treatmentsession.
 22. The device of claim 20, wherein the delimiting parametercomprises a total amount of delivered energy for the treatment session.23. A self-contained, hand-held device for providing a dermatologicaltreatment, the device comprising: a device body configured to behandheld by a user; a laser supported in the device body, the laserincluding a laser beam source configured to generate an energy beam; anapplication end configured to be manually moved across the surface ofthe skin during a treatment session; electronics configured to pulse thelaser during the treatment session such that the laser beam source emitsa sequence of pulsed energy beams to the skin to generate an array oftreatment spots on the skin, wherein adjacent treatment spots generatedon the skin are spaced apart from each other by areas of non-treatedskin between the adjacent treatment spots, thereby providing afractional treatment; and a displacement control system including: adisplacement sensor configured to determine a displacement of the devicerelative to the skin; and electronics configured to control at least oneoperational parameter of the device based on the determined displacementof the device relative to the skin.
 24. The device of claim 23,comprising electronics configured to control at least one operationalparameter of the laser based at least on the determined displacement ofthe device relative to the skin.
 25. The device of claim 23, wherein thedevice includes a single laser that includes a single laser beam source.26. The device of claim 23, wherein the device includes a laser thatincludes multiple laser beam sources.
 27. A self-contained, hand-helddevice for providing a dermatological treatment, the device comprising:a device body configured to be handheld by a user; a radiation sourcesupported in the device body, the radiation source including a beamsource configured to generate an energy beam; an application endconfigured to be manually moved across the surface of the skin during atreatment session; electronics configured to pulse the radiation sourceduring the treatment session such that the beam source emits pulsedenergy beams to the skin; and a displacement control system including: adisplacement sensor configured to determine a displacement of the devicerelative to the skin; and electronics configured to control at least oneoperational parameter of the device based on the determined displacementof the device to provide a defined minimum spacing between adjacenttreatment spots.
 28. A self-contained, hand-held device for providing adermatological treatment, the device comprising: a device bodyconfigured to be handheld by a user; a radiation source supported in thedevice body, the radiation source including a beam source configured togenerate an energy beam; an application end configured to be manuallymoved across the surface of the skin during a treatment session;electronics configured to pulse the radiation source during thetreatment session such that the beam source emits pulsed energy beams tothe skin; and a displacement control system programmed to: automaticallyidentify intrinsic skin features in the skin proximate the applicationend of the device; and control at least one operational parameter of thedevice based on the identification of intrinsic skin features in theskin.
 29. The device of claim 28, wherein the displacement controlsystem is configured to: analyze signals from a displacement sensor toidentify intrinsic skin features in the skin; count the number ofidentified intrinsic skin features; and control at least one operationalparameter of the device based on the counted number of identifiedintrinsic skin features.
 30. The device of claim 28, wherein thedisplacement control system is configured to control the radiationsource to provide a defined minimum spacing between adjacent treatmentspots.
 31. A self-contained, hand-held device for providing adermatological treatment, the device comprising: a device bodyconfigured to be handheld by a user; a radiation source supported in thedevice body, the radiation source including a beam source configured togenerate an energy beam; an application end configured to be manuallymoved across the surface of the skin during a treatment session;electronics configured to pulse the radiation source during thetreatment session such that the beam source emits pulsed energy beams tothe skin; and a single-pixel sensor configured to generate signals basedon an interaction with the skin; and electronics configured to controlat least one operational parameter of the radiation source based on thesignals from the single-pixel sensor.
 32. The device of claim 31,wherein the single-pixel sensor is configured to generate signalsrelated to a displacement of the device relative to the skin.
 33. Thedevice of claim 31, wherein the single-pixel sensor is configured togenerate signals related to a speed of the device relative to the skin.34. The device of claim 31, wherein the single-pixel sensor isconfigured to generate signals indicating whether or not the device ismoving relative to the skin.
 35. The device of claim 31, wherein thesingle-pixel sensor is configured to generate signals indicating whetheror not the device is in contact with the skin.
 36. The device of claim31, wherein the single-pixel displacement sensor includes: a lightemitter configured to deliver light toward the skin; a light detectorconfigured to detect light reflected and/or remitted from the skin, andgenerate a signal; and control electronics for analyzing a signal fromthe detector.
 37. The device of claim 31, comprising electronicsprogrammed to: analyze signals from the single-pixel sensor to identifyskin features in the skin; count the number of identified skin features;and control one or more operational aspects of the device based on thecounted number of identified skin features.
 38. The device of claim 37,comprising electronics programmed to control the radiation source basedon the counted number of identified skin features.
 39. The device ofclaim 37, comprising electronics programmed to enable the radiationsource only if the counted number of identified skin features reaches apredetermined minimum number of skin features.